COVID-19 Vaccine frequently asked questions

Last updated April 30, 2021.

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Vaccination bottles

Top 10 most frequently asked questions

  • Right now, Colorado is in phase 2 of vaccine distribution. All Coloradans 16 and older are eligible to receive the Pfizer vaccine, and all Coloradans 18 and older are eligible to receive the Moderna or Janssen (Johnson & Johnson) vaccine.

  • Anyone younger than 16 years old should not get a vaccine unless they are enrolled in a clinical trial. 

  • While vaccines are now available to the general public, vaccine supply is still dependent on weekly shipments from the federal government. Supply remains limited at this time.

  • It’s important to know that vaccine providers may have varying amounts of vaccine during any given week. Vaccine providers are working as fast as they can to set up appointments for when they have the vaccine. Note that these locations are not open for walk-in appointments. They should be contacted directly for more information. 

  • Members of the general public (age 16 and over) may contact a local vaccine provider or local public health department to learn more about scheduling a vaccine appointment.

  • Health care workers and first responders in 1A or 1B: If your employer has not contacted you about getting a vaccine, contact a vaccine provider near you or your local public health department.

  • Long-term care facility staff and residents should expect to receive the vaccine through the federal government's Pharmacy Partnership for Long-term Care (LTC) program.

  • P-12 educators: Educators and staff should check with their employers first. Many school districts, public and private schools, and the Board of Cooperative Educational Services (BOCES) have already begun planning with local health care partners, including hospital systems, clinics, and local public health agencies, to schedule vaccinations for educators. School districts and schools that need assistance connecting with a COVID-19 vaccine provider and/or making a COVID-19 vaccination plan for their staff members can fill out CDPHE’s COVID-19 Vaccination School/Child Care Assistance Request form.

  • Child care providers in licensed child care programs (which includes licensed child care centers, preschools, school-age child care and licensed family child care providers): The best way to get you or your staff vaccinated is by individually enrolling with vaccine providers. In some counties, your local public health agency (LPHA) will coordinate vaccinations, either directly with a provider or with scheduled clinics. Licensed child care programs that need assistance connecting with a COVID-19 vaccine provider and/or making a COVID-19 vaccination plan for their staff members can fill out CDPHE’s COVID-19 Vaccination School/Child Care Assistance Request form. If more clarity is needed regarding a certain program's eligibility to receive a vaccine, child care providers can call child care licensing for more information 303-866-5948.

  • Frontline workers 

    • People working in the following fields who cannot maintain physical distance from others at their place of employment and who currently work in close contact with many people, especially indoors and with poor ventilation, may contact their employer about scheduling a vaccine appointment.

      • Agriculture.
      • Food processing.
      • Grocery.
      • Higher education.
      • Food/restaurant services.
      • Manufacturing.
      • US postal service.
      • Public transit and specialized transportation.
      • Public health.
      • Human services.
      • Faith leaders.
      • Direct care providers for Coloradans experiencing homelessness.
      • Journalists.
  • If your employer is not offering vaccinations, you may contact a local vaccine provider listed on the state’s Find out where you can get vaccinated web page. You may be asked to provide a recent pay stub to verify you are in this phase. If you are an employer that needs help connecting with a provider to vaccinate your employees, please fill out the Frontline Essential Worker Survey

  • People who currently work in grocery stores in close contact with others may schedule a vaccine appointment through their store’s pharmacy. If you work in a grocery store that does not have a pharmacy, you may contact your local public health agency about scheduling a vaccine appointment. You may be asked to provide a recent pay stub to verify you are in this phase.

  • People age 16-49 with high-risk conditions: Anyone with one of the following conditions is eligible under 1B.4:

    • Asthma (moderate to severe) 
    • Cancer (if you are currently receiving treatment or have received treatment within the last month) 
    • Cerebrovascular disease (affects blood vessels and blood supply to the brain) 
    • Chronic kidney disease 
    • COPD 
    • Cystic fibrosis 
    • Diabetes (type 1 and 2) 
    • Disabilities that require direct care at home 
    • Disabilities that prevent mask-wearing 
    • Down syndrome 
    • Heart failure, cardiomyopathies or coronary heart disease, or severe valvular/congenital heart disease 
    • HIV 
    • Hypertension/high blood pressure 
    • Immunocompromised state (weakened immune system) from a blood or bone marrow transplant 
    • Immune deficiency 
    • Liver disease 
    • Neurologic conditions (such as dementia) 
    • Obesity (BMI of 30 or more) 
    • Pregnancy 
    • Pulmonary fibrosis (damaged or scarred lung tissues) 
    • Sickle cell disease 
    • Solid organ transplant 
    • Thalassemia (a type of blood disorder) 
    • Use of corticosteroids or other immune-weakening medicines
  • You will be asked to self-attest that you have a high-risk conditions. People with two or more high risk conditions should view the vaccine providers on the state’s Find out where you can get vaccinated web page or try contacting a vaccine provider near you.

  • If you need help finding out where you can receive a vaccine or who to contact in your community, call 1-877-COVAXCO (1-877-268-2926) 24 hours a day, 7 days a week. Multiple languages are available.

  • All Coloradans age 16 and over are now eligible for a vaccine. However, vaccine supply remains limited at this time, and appointments may not be immediately available for all Coloradans who want a vaccine.

  • Visit the Find out where you can get vaccinated web page for more information about how to sign up for a vaccine appointment.

  • After getting fully vaccinated, it’s important to continue taking precautions while you are in public and at work, like wearing a well-fitting mask and keeping at least 6 feet of physical distance from other people. This is because you might still be able to spread the virus to unvaccinated people.
  • People are considered fully vaccinated: 
    • 2 weeks after their second dose in a 2-dose series, like the Pfizer or Moderna vaccines. 
    • 2 weeks after a single-dose vaccine, like Janssen’s (Johnson & Johnson) vaccine.
  • If you are fully vaccinated, you may visit other people who have been fully vaccinated indoors without wearing masks or physically distancing in small groups.
  • If you are fully vaccinated, you may also visit with unvaccinated people from a single household who are at low risk for severe COVID-19 disease indoors without wearing masks or physical distancing. 
  • We recommend continuing to avoid medium and large gatherings with multiple households even after vaccination. 
  • For more information about precautions you should take after vaccination, please see CDC’s webpage When You’ve Been Fully Vaccinated: How to Protect Yourself and Others
  • Learn more about how to protect yourself in this FAQ.

  • No. It is not possible to get COVID-19 from a vaccine, but you may feel some side effects like fever, chills, and fatigue. The current COVID-19 vaccines use temporary pieces of genetic code from the virus to stimulate your body’s immune response. This cannot cause COVID-19. The goal of each vaccine is to provide your body with the tools it needs to fight the COVID-19 virus if you were to get infected. 

  • Learn more about vaccine side effects and immunity in this FAQ.

  • It is currently unknown how long natural immunity lasts after recovering from COVID-19. Early evidence suggests natural immunity from COVID-19 may not last very long in some people, and cases of reinfection have been reported. So even if you have had COVID-19 and recovered, you should plan to get a vaccine when it is your turn. 

  • If you had a COVID-19 infection, CDC says you may wait a few months after your infection before getting the vaccine as re-infection risk is low during this time. However, you may choose to get the vaccine earlier than that as long as you have recovered from your infection.

  • If you received a COVID-19-specific antibody treatment (e.g. monoclonal antibodies or convalescent plasma) while you were sick with COVID-19, you should wait at least 90 days after receiving the antibody treatment before getting the vaccine. 

  • Data from clinical trials suggest that the Pfizer and Moderna vaccines are safe and effective in people who have recovered from a previous COVID-19 infection.

  • Learn more about immunity in this FAQ. 

  • The vaccine is free. Providers should not ask you to pay for the vaccine or other administrative costs, regardless of your insurance status. If you have insurance, the provider may seek reimbursement from your health insurance company for these fees, but you should not be charged. 

  • In the unlikely event that your provider requires payment for your vaccine appointment, you should ask questions about what you are being charged for and why. You should ask for an itemized bill or receipt from the provider and then seek reimbursement from your insurance company.

  • If a vaccine provider is demanding payment, you can report them by filling out the following form: covid19.colorado.gov/VaccineConcerns. You can also call 1-877-COVAXCO (1-877-268-2926) 24 hours a day, 7 days a week. Multiple languages are available.

  • If you encounter problems with your insurance company, you can contact the Division of Insurance by phone at 303-894-7490 or by email at DORA_Insurance@state.co.us.

  • If someone is making you pay for a vaccine or a vaccine appointment, it may be a scam. You can report potential vaccine scams to the Colorado Attorney General’s Office at stopfraudcolorado.gov.

  • Learn more about getting the vaccine in this FAQ.

  • No. You do not need to be a U.S. citizen, and you will not need to prove lawful presence to get a COVID-19 vaccine in Colorado.

  • Know that the Department of Homeland Security announced that vaccination sites will be considered sensitive locations. This means that ICE will not carry out enforcement activities at or near vaccination sites. 

  • State and local public health agencies will never share your information for any immigration or law enforcement purposes. And receiving the COVID-19 vaccine will not count against you in any public charge determinations.

  • If a vaccine provider is demanding identification, you can report them by filling out the following form: covid19.colorado.gov/VaccineConcerns. You can also call 1-877-COVAXCO (1-877-268-2926) 24 hours a day, 7 days a week. Multiple languages are available.

  • Learn more about getting the vaccine in this FAQ.

  • In developing a vaccine for COVID-19, researchers had to work quickly, but not at the risk of anyone’s safety. Medical researchers did not cut any corners or skip any steps. Safety and effectiveness were the top priorities. 

  • The timeline for developing COVID-19 vaccines was possible for several reasons: 

    • Researchers relied on years of previous research in other viruses and vaccines to help inform a vaccine development process for COVID-19. 

    • Everyone involved dedicated all their resources and time to developing a COVID-19 vaccine. This includes research institutions, pharmaceutical companies, government agencies, and philanthropic organizations. 

    • Many governments around the world, including the U.S. government, and private funders invested in the vaccine, which allowed pharmaceutical companies to focus on research right away. 

    • Finally, because of the financial support, researchers were able to conduct different parts of the development process on parallel tracks instead of one after another. Usually, each phase in a clinical trial ends before the next phase begins, with several months to a year or more in between each phase. Because of the emergency presented by the pandemic, researchers developed the vaccines on parallel tracks, meaning that they completed the necessary steps at the same time or with some overlap. No steps were skipped in the process of developing the COVID-19 vaccines. 

  • Learn more about vaccine safety in this FAQ.

Frequently Asked Questions by topic

Getting a COVID-19 vaccine

  • Currently, the U.S. Food and Drug Administration (FDA) has authorized three COVID-19 vaccines from the companies Pfizer, Moderna, and Janssen (Johnson & Johnson). The FDA authorized the Pfizer vaccine for people 16 years and older and authorized the Moderna vaccine and Janssen (Johnson & Johnson) vaccines for adults 18 and older.

  • CDC provides detailed profiles for each available vaccine on their Different COVID-19 Vaccines page.

  • None of the vaccines is recommended over the other for adults 18 and over. Teens age 16 and 17 can currently only get the Pfizer vaccine. If you are an adult, we encourage you to get whichever vaccine type or product is offered to you. Getting vaccinated greatly reduces the risk of illness if you are exposed to the virus. 

  • Learn more about how COVID-19 vaccines work in this FAQ.

  • No. Minors may go to their vaccine appointments unaccompanied as long as parental consent is collected and shared prior to the appointment. This can be done through Colorado’s COVID-19 Vaccine Screening and Administration Form (view in Spanish) or through the vaccine provider’s online scheduling system. The provider may also obtain consent by phone and document it in the patient’s record.

  • The Pfizer vaccine is authorized for people who are age 16 and older. The Moderna and Janssen (Johnson & Johnson) vaccines are authorized for adults 18 and up. Anyone younger than 16 years old should not get a vaccine unless they are enrolled in a clinical trial. 

  • Although children as young as 12 years old have been enrolled in vaccine studies, the FDA has not yet authorized any COVID-19 vaccine for children under the age of 16. 

  • Any vaccine use for younger children would only come after appropriate clinical trials and authorization by the FDA. We will continue to monitor the Pfizer and Moderna clinical trials currently underway with the goal of making a COVID-19 vaccine available for children in the future, and we will update our vaccine protocols if further authorizations are provided under guidance from the FDA and CDC.

  • The Janssen (Johnson & Johnson) vaccine requires one dose. The Pfizer and Moderna COVID-19 vaccines require two doses. Pfizer doses should be given 21 days apart and Moderna doses should be given 28 days apart.  

  • If it isn’t possible to get the second dose on the right day, the second dose can be given early, up to 4 days before it is due. Additionally, the second dose can be given as late as 42 days (6 weeks) after the first dose. This is called a grace period. 

  • COVID-19 mRNA vaccines are not meant to be not interchangeable. The second dose of any COVID-19 vaccine should be completed with the same vaccine product as the first dose.

  • Learn more about getting your second dose in this FAQ.

  • Yes, it is fine to take all prescription drugs as usual.

  • Avoid taking over-the-counter pain or fever medications before getting vaccinated. There is a theoretical possibility that doing so might reduce vaccine effectiveness. 

  • If it is normally safe for you to do so, you can take over-the-counter pain or fever medication after you receive the vaccine and once you start to feel side effects.

  • CDC recommends waiting a minimum of 14 days before and after the administration of other vaccines before getting any dose of COVID-19 vaccine. This is because there isn’t enough data on the safety and efficacy of COVID-19 vaccines that are given at the same time as other vaccines. However, in situations where the benefits of both vaccinations are considered to outweigh the potential unknown risks, a COVID-19 vaccine and other vaccines may be administered sooner than 14 days.

  • The vaccine is free. Providers should not ask you to pay for the vaccine or other administrative costs, regardless of your insurance status. If you have insurance, the provider may seek reimbursement from your health insurance company for these fees, but you should not be charged.

  • Providers are not allowed to turn you away because of an inability to pay or your current medical coverage status. Medicare, Medicaid, and private insurance are required to cover the cost of the COVID-19 vaccines. If you do not have health insurance, providers may seek reimbursement for your appointment through the Provider Relief Fund through the Health Resources and Services Administration (HRSA).

  • In the unlikely event that your provider requires payment for your vaccine appointment, you should ask questions about what you are being charged for and why. You should ask for an itemized bill or receipt from the provider and then seek reimbursement from your insurance company.

  • If you encounter problems with your insurance company, you can contact the Division of Insurance by phone at 303-894-7490 or by email at DORA_Insurance@state.co.us.

  • If someone is making you pay for a vaccine or a vaccine appointment, it may be a scam. You can report potential vaccine scams to the Colorado Attorney General’s Office at stopfraudcolorado.gov.

  • Like other routine vaccinations, you will need to share some personal information with your vaccine provider when you get a COVID-19 vaccine. This may include your name, date of birth, and contact information. Your privacy is a top priority, and your information will not be used for anything other than vaccine distribution and follow-up information about the vaccine. 

  • Sharing your identity and some of your medical history ensures that the vaccine is administered safely, effectively, and responsibly. Your individual immunization records are confidential, personal medical information, and public health will never share them publicly. 

  • The state health department maintains the Colorado Immunization Information System (CIIS), a confidential, population-based, secure computerized system that collects and consolidates individual-level vaccine and exemption data for Coloradans of all ages from a variety of sources. Health care providers have limited access to CIIS based on their need to input and access data for their patients. 

  • Under Colorado law, you can choose to remove your immunization information from CIIS at any time. This is called an opt-out. 

  • The state health department submits daily, anonymous COVID-19 vaccine administration data to the CDC as required. The state worked to ensure that no personally identifiable information like your name or full address will be shared with CDC.

  • You do not need a government-issued ID like a driver’s license or passport to get the vaccine. Some medical forms may have a field to enter your social security number, but you are not required to complete it.

  • If a provider is requiring you to show identification in order to get vaccinated, you can submit a report using the state’s COVID-19 Concerns form.

No. People do not need to be full-time residents of Colorado, nor of a particular Colorado county, to be vaccinated by enrolled providers. If people meet eligibility criteria in Colorado's Phased Prioritization, they should be vaccinated in the same way as other eligible Coloradans.

  • The CDC does not recommend getting tested before getting the vaccine. If you do not have any symptoms and have not been recently exposed to COVID-19, there is no need to get a test before deciding whether or not to get vaccinated.

Getting your second dose of Pfizer or Moderna vaccine

  • We strongly recommend that you get both doses from the same vaccine provider. Doing so ensures that you are getting the same vaccine product for both doses at the right time. 

  • Note that the second dose should be the same vaccine product as the first dose.

  • You should make every effort to receive the second dose of your COVID-19 vaccine exactly 21 days after the first dose for Pfizer and 28 days after the first dose for Moderna. Plan accordingly so that you are able to get the second dose of your vaccine at the right time.

  • If it isn’t possible to get the second dose on the right day, the second dose can be given early, up to 4 days before it is due. Additionally, the second dose can be given as late as 42 days (6 weeks) after the first dose. This is called a grace period. 

  • There is not a lot of data on how well the vaccine will work if given outside of the grace period. But if the second dose is accidentally given outside the grace period, there is no need to restart the vaccination series.

  • Every effort should be made to make sure your second dose is the same vaccine product as the first dose. Studies have shown that the vaccines are safe and work well when the same vaccine product is used for both doses. 

  • If, for some reason, you receive a different product for your second dose, you do not need to repeat the vaccination again with additional doses.

  • Although current studies show that it takes two doses of the Pfizer or Moderna vaccine to be 95% effective, there is no evidence that taking only one dose will have any harmful effects on your health. If you do not receive the second dose, you will not be fully immunized and be at higher risk of getting symptomatic COVID-19 than if you received both doses.

Vaccine side effects

  • You may experience mild to moderate side effects after receiving the vaccine. Side effects typically go away on their own after a few days. The most commonly reported side effects are: 

    • Pain, swelling, and redness at the injection site.

    • Pain, tenderness and swelling of the lymph nodes in the same arm of the injection.

    • Fatigue.

    • Headache.

    • Muscle pain.

    • Chills.

    • Joint pain.

    • Nausea/vomiting.

    • Fever.

  • Different people may experience different side effects, even if they receive the same vaccine. 

  • The process of building immunity can cause symptoms. These symptoms are normal and show that your body’s immune system is responding to a vaccine. Other routine vaccines, like the flu vaccine, have similar side effects.

  • If you experience discomfort after the first dose of the Pfizer or Moderna vaccine, it is very important that you still receive the second dose a few weeks later for full protection.

  • For in-depth information about the side effects of the vaccines, see the CDC’s report on the Pfizer vaccine, the Moderna vaccine, and the Janssen (Johnson & Johnson) vaccine.

  • Some people have reported experiencing dizziness, lightheadedness, feeling faint, rapid breathing, and sweating symptoms immediately following COVID-19 vaccines in several states, including Colorado. 

  • On April 7, 11 people reported symptoms like these at the Dick’s Sporting Goods Community Vaccination Site in Colorado. EMS transported two of the patients to the hospital for observation, and treated the other nine people with juice and water. The two patients transported to the hospital were released from the emergency department and were not admitted. Vaccinations at the site were temporarily paused, then resumed after public health found no cause for concern.

  • Feeling anxious or faint can be common when receiving any vaccination or going through any kind of medical procedure, like a blood draw. When you go to your vaccine appointment, bring a beverage and a snack or a friend or family member to help offer some reassurance. Let clinical staff know if you are feeling faint, as they may need to put your feet up temporarily or give you something to drink. Learn more about fainting after vaccination from the CDC. 

  • CDC, FDA, and other federal partners will continue to monitor the safety of COVID-19 vaccines.

  • Learn more about the Safety of Vaccines.

  • If you get a COVID-19 vaccine and you think you might be having a severe allergic reaction after leaving the vaccination site, seek immediate medical care by calling 911.

  • In most cases, discomfort from fever or pain after getting the vaccine is normal. Contact your doctor or health care provider:

    • If the redness or tenderness where you got the shot increases after 24 hours.

    • If your side effects are worrying you or do not seem to be going away after a few days.

  • The side effects after the second dose of a Pfizer or Moderna vaccine might be more intense or cause more discomfort than side effects after the first dose. In some cases, the side effects may be bad enough to interfere with your work and other normal daily activities for a day or two. 

  • If you are experiencing more intense side effects, stay well hydrated, rest, and consider  over-the-counter medications like acetaminophen or ibuprofen (if they are normally safe for you to take). Side effects are proof that your body is building immunity in response to the vaccine and will typically go away on their own within a day or two. 

  • Even if you experience discomfort from the vaccine, it is important that you receive both doses for full protection.

  • For more information about the second dose of the vaccine, see the “Getting your second dose of vaccine” section of this FAQ.

  • Because the body has already responded to one dose of the vaccine, the second dose may cause a stronger immune response in your body. These side effects are expected and show that your body is continuing to build immunity. It is okay if you do not feel any side effects, it doesn’t mean the vaccine isn’t working.

  • Side effects from the vaccine typically occur one to two days after receiving the vaccine and can include fever, chills, headache, and fatigue. If you experience the expected side effects within one or two days of receiving a vaccine, it likely means that you are not contagious and do not need to isolate. 

  • The currently authorized vaccines  do not contain the virus that causes COVID-19 disease. All currently authorized vaccines are inactivated. The Janssen (Johnson & Johnson) vaccine contains modified adenovirus, a different, harmless virus, but this virus cannot replicate itself or make you sick.

  • Cough, shortness of breath, nasal congestion, sore throat, or loss of taste or smell are not recognized side effects of the vaccine and may indicate COVID-19 infection (or another infection). 

  • Learn more about quarantine and isolation guidance for people who are vaccinated in this FAQ.

  • Yes. Different people will respond differently to the vaccines. While many people will have side effects, some people will not. Even if you do not get side effects, the vaccine is likely working.

  • Although it is rare, the COVID-19 vaccines may cause mild allergic reactions in some people, like itching or rash. In extremely rare cases, some people may have a severe allergic reaction (e.g.anaphylaxis). If this occurs, vaccination providers can effectively and immediately treat the reaction.

  • Anaphylaxis after receiving a COVID-19 mRNA vaccine is rare and occurs in approximately 2 to 5 people for every million vaccinated based on events reported to Vaccine Adverse Event Reporting System (VAERS). Similar data are not available yet for the Janssen (Johnson & Johnson) vaccine.

  • The health care provider administering your vaccine will monitor you for any allergic reactions you may have after getting vaccinated. They will watch you for at least 15 minutes after the injection (or for 30 minutes if you have a history of anaphylaxis or if you have had an immediate allergic reaction of any severity to a vaccine or injectable therapy). 

  • If you had a reaction following a vaccination, contact your health care provider. You can also submit a report to the Vaccine Adverse Event Reporting System (VAERS).

  • People with a history of severe allergic reactions to any ingredient of a COVID-19 vaccine should not receive that vaccine. For a full list of ingredients, please see each vaccine’s fact sheet (ModernaPfizer, or Janssen (Johnson & Johnson)). Neither vaccine contains eggs, preservatives, or latex. 

  • Additionally, people who have had an immediate allergic reaction (within seconds or minutes) of any severity to previous doses of a COVID-19 vaccine, its components, or to polysorbate should not receive additional doses.  

  • People who have had severe allergic reactions to other vaccines or injectable therapies in the past should use caution and talk with their health care provider before deciding whether to get vaccinated. 

  • People with a history of severe allergic reactions unrelated to any vaccine or injectable therapy may get the COVID-19 vaccine.

  • If you get a serious physical injury as a direct result of the COVID-19 vaccine, you can file a claim for medical expenses, lost employment income, and survivor death benefits with the Countermeasure Injury Compensation Program (CICP).

  • You do not need to be a U.S. citizen to file a claim or receive benefits from the Countermeasure Injury Compensation Program (CICP) if you qualify.

  • Under Colorado’s Healthy Families and Workplaces Act (HFWA), you are entitled to paid sick leave from your employer. Among other situations, the law requires employers to provide paid leave for employees who have an illness, injury, or health condition that prevents them from working. Paid sick leave must also be available if the employee is getting preventative care such as a vaccination. 

  • During a public health emergency, all employers, regardless of the size of the company, must immediately provide each employee additional paid leave. For example, employees who normally work 40 or more hours a week are entitled to 80 hours of paid sick leave. 

  • For more information about HFWA, please visit the Colorado Department of Labor and Employment’s website.

Health conditions and the vaccine

  • Yes. Pregnant or breastfeeding people may choose to be vaccinated. Talking to a health care provider may help with deciding whether to get the vaccine, but it is not required for vaccination.

  • Based on current knowledge, experts believe that the currently authorized COVID-19 vaccines are unlikely to pose a risk for pregnant or breastfeeding people or their babies. However, pregnant and breastfeeding people were not included in any of the clinical trials for currently authorized COVID-19 vaccines so there is little data on the  safety of the vaccines in pregnant or breastfeeding people. Data show that while the overall risk for pregnant people with COVID-19 is low, they do have an increased risk of severe illness or death.

  • Currently authorized COVID-19 vaccines are not thought to be a risk to breastfeeding babies.

  • The Academy of Breastfeeding Medicine recommends that lactating individuals who get the vaccine continue breastfeeding their babies after being vaccinated. Breast milk contains antibodies and other components that can boost babies’ immune systems and protect babies from getting sick. Early research has shown COVID-19 antibodies are present in breast milk. It is believed that antibodies created after a breastfeeding individual receives the vaccine may also transfer into breast milk and could provide some protection to the baby.

  • For more information about COVID-19 vaccines and pregnancy, see CDPHE’s Pregnancy and breastfeeding FAQ.

  • Immunocompromised people may receive a COVID-19 vaccine if they have no contraindications or reason to believe that getting the vaccine would be harmful to them. However, it is important to talk to your health care provider if you have questions about the unknown safety and effectiveness of the vaccine in immunocompromised populations, as well as the potential for reduced immune responses.

  • People living with HIV, other immunocompromising conditions, or who take immunosuppressive medications or therapies might be at increased risk for severe COVID-19 disease. There is currently not enough data to establish vaccine safety and efficacy in these groups. 

  • People with stable HIV infection were included in phase 2 and 3 clinical trials, though data specific to this group are not yet available. 

  • None of the currently available vaccines contains the virus that causes COVID-19.s. A COVID-19 vaccine cannot give you COVID-19.

How COVID-19 vaccines work

  • All available vaccines are shown to be highly effective at preventing moderate, severe, and critical COVID-19 illness, hospitalization and death.. 
  • Getting any authorized COVID-19 vaccine will give you more protection than not getting a COVID-19 vaccine. All authorized COVID-19 vaccines are effective tools in stopping the crisis brought on by the pandemic as quickly as possible. 

  • Directly comparing effectiveness rates between vaccines can be difficult because the clinical trials for each one were designed differently and measured results in different ways and in different populations at different times.
    • Pfizer reported that after 7 days, their vaccines are about 95% effective at preventing the onset of any COVID-19 symptoms. Moderna concluded a 94% effectiveness rate at 14 days. 
    • Janssen (Johnson & Johnson) has reported that, globally, its vaccine is 66% effective at preventing moderate to severe/critical COVID-19 symptoms after 28 days. The Janssen trial also concluded that the vaccine is about 86% effective at preventing severe or critical COVID-19 illness in U.S. participants after 28 days. 
  • All three vaccines work very well to prevent you from getting very sick from COVID-19. 
  • As long as supply is limited, the best vaccine is the one you are able to get the soonest. The more people are vaccinated, the closer we can get to the end of the pandemic.

None of the currently authorized vaccines contain the SARS-CoV-2 virus, the virus that causes COVID-19 disease. All currently authorized vaccines are inactivated. The Janssen (Johnson & Johnson) vaccine contains a modified adenovirus, a different, harmless virus, but this virus cannot replicate itself or make you sick.

  • All authorized COVID-19 vaccines teach your body how to make spike proteins like the ones that cover the COVID-19 virus. Your body learns how to fight the spike protein without having to fight off the full virus. If you are exposed to a person with COVID-19 after vaccination, your body will recognize the spike proteins and remember how to fight them before the virus makes you sick.
  • While all COVID-19 vaccines contain instructions for how to make spike proteins, these instructions are written in different ways. Viral vector vaccines, like the Janssen (Johnson & Johnson) vaccine, use a piece of double-stranded DNA to teach your body how to fight COVID-19. mRNA vaccines, like the Pfizer and Moderna vaccines, use single-stranded mRNA. The goal of every vaccine is the same -- they just use a different strategy to achieve that goal.
  • Janssen’s (Johnson & Johnson) vaccine is more durable than either of the authorized mRNA vaccines. It can be stored for up to three months at normal refrigeration temperatures (36–46°F or 2–8°C).
  • The Janssen (Johnson & Johnson) vaccine only requires one dose. The Pfizer and Moderna vaccines require two doses.

  • The Pfizer and Moderna vaccines are both mRNA vaccines. These vaccines help our bodies build an immune response to the COVID-19 virus. The mRNA vaccine temporarily teaches our cells how to make a harmless spike protein that is unique to the virus that causes COVID-19. After our cells temporarily make copies of the protein, our immune system recognizes that the protein should not be in our body and builds antibodies to remember how to fight the virus if we are infected in the future. 

  • An antibody is a protein produced by your immune system that can recognize a specific type of virus in your body. When you get exposed, your body’s antibodies are able to recognize proteins on the surface of the COVID-19 virus to attack and stop it from replicating in your body.

  • For a visual explanation of how mRNA vaccines work, watch Stat’s video “What are mRNA vaccines?”

  • To learn more, visit CDC’s Understanding How COVID-19 Vaccines Work.

  • The Janssen (Johnson & Johnson) vaccine is a viral vector vaccine. Like mRNA vaccines, viral vector vaccines help our bodies build an immune response to the COVID-19 virus. Viral vector vaccines temporarily teach our cells how to make a harmless spike protein that is unique to the virus that causes COVID-19. 
  • While mRNA vaccines use single-stranded genetic code called mRNA to write down instructions for this protein, viral vector vaccines use double-stranded DNA. Scientists put this DNA into a different virus called Adenovirus 26. Adenoviruses are common viruses that typically cause colds or flu-like symptoms. The Janssen (Johnson & Johnson) vaccine uses a modified adenovirus that can give your cells instructions about how to make spike proteins. This adenovirus can’t make you sick.
  • After our cells temporarily make copies of the protein, our immune system recognizes that the protein should not be in our body and builds antibodies to remember how to fight the virus if we are exposed in the future. 
  • An antibody is a protein produced by your immune system that can recognize a specific type of virus in your body. When you get exposed, your body’s antibodies are able to recognize proteins on the surface of the COVID-19 virus to attack and stop it from replicating in your body.
  • To learn more, visit CDC’s Understanding Viral Vector COVID-19 Vaccines.

  • No, mRNA from the COVID-19 vaccines does not affect your DNA. mRNA is a naturally occurring and temporary genetic molecule that instructs your cells how to create spike proteins in the body. Minutes to hours after the mRNA is read by the cell, the body destroys the temporary mRNA using a special enzyme. After your cells make copies of the virus’ protein, your immune system is triggered and recognizes that the protein should not be in your body. Your body then builds antibodies so that it remembers how to fight the virus if you are exposed in the future.

  • No, the DNA delivered by the viral vector won’t make any long-term changes to your body’s genes. The DNA goes into some of your cells to give temporary instructions on how to make spike proteins. When the vaccinated cells die, the DNA does not affect any other cells. Viral vector vaccines cannot change your body’s genome.
  • After your cells make copies of the virus’ protein, your immune system is triggered and recognizes that the protein should not be in your body. Your body then builds antibodies so that it remembers how to fight the virus if you are exposed in the future.

Safety of the vaccines

For additional information, visit CDC: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety.html.

  • Serious side effects (also known as adverse events) are extremely rare. The federal government takes all reports of vaccine adverse events seriously. 

  • CDC and FDA reviewed data involving six reported U.S. cases of a rare and severe type of blood clot in people who received the Janssen (Johnson & Johnson) vaccine. They found that this vaccine may be associated with an increased risk of very rare but potentially severe blood clots, now called thrombosis with thrombocytopenia syndrome or TTS, particularly among women under the age of 50. Approximately seven cases of TTS per 1,000,000 vaccine doses have been identified in women under 50 to date.

    • The FDA and CDC have confidence that the Janssen vaccine is safe and effective in preventing COVID-19.

    • CDPHE has sent information to health care providers to inform them about how to identify and treat TTS in the very rare case it were to occur. The FDA and CDC have confidence that this vaccine is safe and effective in preventing COVID-19.

    • The FDA has determined that the available data show that the vaccine’s known and potential benefits outweigh its known and potential risks in individuals 18 years of age and older.

    • At this time, the available data suggest that the chance of TTS occurring is very low, but the FDA and CDC will remain vigilant in continuing to investigate this risk.

    • Health care providers administering the vaccine and vaccine recipients or caregivers should review the Janssen COVID-19 Vaccine Fact Sheet for Healthcare Providers Administering Vaccine (Vaccination Providers) and Fact Sheet for Recipients and Caregivers, which have been revised to include information about the risk of this syndrome, which has occurred in a very small number of people who have received the Janssen COVID-19 Vaccine.

    • People who have received the Janssen vaccine who develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their health care provider.

  • CDC uses many vaccine safety monitoring systems, including the Vaccine Adverse Event Reporting System (VAERS), to watch for adverse events after vaccination. VAERS is useful for quickly detecting unusual or unexpected patterns of adverse event reporting that might signal a possible safety problem with a vaccine. 

  • VAERS accepts reports of any adverse event following vaccination, even if it is not clear that the vaccine caused a serious side effect. 

  • CDC, FDA, and other federal partners will continue to monitor the safety of COVID-19 vaccines. Find out more on CDC’s Selected Adverse Events Reported after COVID-19 Vaccination.

  • To date, the CDC has not found any patterns in cause of death that would suggest a safety problem with COVID-19 vaccines.

  • Given the natural rate of deaths in the population, some people have died after receiving the vaccine, but that's because there are deaths every day from a variety of causes. 

  • Reports of death following vaccination do not necessarily mean the vaccine caused the death. 

  • CDC follows up on any report of death to request additional information and learn more about what occurred and to determine whether the death was caused by the vaccine or if it was unrelated.

  • CDC, FDA, and other federal partners will continue to monitor the safety of COVID-19 vaccines. Find out more on CDC’s Selected Adverse Events Reported after COVID-19 Vaccination

  • In developing a vaccine for COVID-19, researchers had to work quickly, but not at the risk of anyone’s safety. Medical researchers did not cut any corners or skip any steps. Safety and effectiveness were the top priorities. 

  • The timeline for developing COVID-19 vaccines was possible for several reasons: 

    • Researchers relied on years of previous research in other viruses and vaccines to help inform a vaccine development process for COVID-19. 

    • Everyone involved dedicated all their resources and time to developing a COVID-19 vaccine. This includes research institutions, pharmaceutical companies, government agencies, and philanthropic organizations. 

    • Many governments around the world, including the U.S. government, and private funders invested in the vaccine, which allowed pharmaceutical companies to focus on research right away. 

    • Finally, because of the financial support, researchers were able to conduct different parts of the development process on parallel tracks instead of one after another. Usually, each phase in a clinical trial ends before the next phase begins, with several months to a year or more in between each phase. Because of the emergency presented by the pandemic, researchers developed the vaccines on parallel tracks, meaning that they completed the necessary steps at the same time or with some overlap. No steps were skipped in the process of developing the COVID-19 vaccines.

  • The FDA requires that vaccines undergo a rigorous scientific process, including three phases of clinical trials, before they authorize or approve the vaccine. The COVID-19 vaccines are subject to the same safety standards as other vaccine trials. 

  • The independent Data and Safety Monitoring Board overseeing Phase 3 trials of the Pfizer, Moderna, and Janssen (Johnson & Johnson) vaccines has not identified or reported any serious safety concerns. All phase 3 studies have Data Safety and Monitoring Boards. The boards are made up of independent scientists hired by the company to look at the safety data and check at regular intervals whether the company should cancel or continue with the study.  

  • Additionally, two independent advisory committees will review a vaccine’s safety data before it is made available to the public. These committees are the Vaccines and Related Biological Products Advisory Committee (VRBPAC), which advises the FDA, and the Advisory Committee on Immunization Practices (ACIP), which advises the CDC.

  • Today’s vaccines use only the ingredients they need to be as safe and effective as possible. Each ingredient in a vaccine serves a specific purpose: provide immunity (protection) and keep the vaccine safe and long-lasting.

  • All vaccines contain antigens or elements that trigger the production of antigens. Antigens make vaccines work. They prompt the body to create the immune response needed to protect against infection. Antigens come in several forms. The form used in a vaccine is chosen because studies show it is the best way to protect against a particular infection. 

  • Other ingredients in vaccines may include preservatives, to keep germs out; adjuvants, to help boost the immune response to the vaccine; and additives, which help the vaccine stay effective while being stored. Each ingredient has a specific function and has been rigorously studied. These ingredients are safe for humans in the amounts used in vaccines.

  • For a full list of ingredients, please see each vaccine’s fact sheet (Moderna, Pfizer, or Janssen).

  • Janssen’s (Johnson & Johnson) vaccine includes ethanol, a form of alcohol, as an inactive ingredient.
  • None of the currently authorized vaccines contain human cells or tissue. However, some human cell lines were used in the production of Janssen’s vaccine. Pfizer and Moderna used human cell lines to test their vaccines.
    • Human cell lines are sometimes used in the early stages of vaccine development because viruses from which those vaccines are made need living cells to reproduce. These cell lines originally came from fetal tissue more than 30 years ago. None of the original tissue remains today: all descended cells are grown in labs. No new fetal tissue is required in the ongoing development and production of vaccines.
    • As with all viral vector vaccines, multiple purification steps ensure that cells are not in the final vaccine product.
    • For more information about human cell lines, please see the College of Physicians of Philadelphia’s webpage Human Cell Strains in Vaccine Development.
  • For a full list of ingredients, please see each vaccine’s fact sheet (Moderna, Pfizer, or Janssen). 
  • If you have ethical concerns about the vaccines, we encourage you to talk to your faith leaders about them.

  • Currently, there is no scientific reason or evidence to suggest COVID-19 mRNA vaccines have any effect on fertility. Clinicians and researchers will continue to closely monitor for any issues. Please talk with your doctor about any concerns.

  • The Food and Drug Administration (FDA) licenses and approves the use of vaccines. Before the FDA approves a vaccine, the manufacturer must do rigorous research and testing to ensure the vaccine’s safety and effectiveness. The FDA independently reviews and verifies the information from these tests. It then decides whether the vaccine can be authorized and given to the public. 

  • In certain emergency situations, the FDA may issue an Emergency Use Authorization (EUA) to provide more timely access to critical medical products when there are no other options available.

  • Vaccines must go through a detailed scientific evaluation before they can be submitted to the FDA for approval. Each phase of the evaluation includes three different clinical research studies. In the clinical research study or trial, people volunteer to be part of the study. Each clinical trial emphasizes safety of the vaccine on people. As the research moves through to the next phase, the group of volunteers becomes bigger to include more diversity in people and circumstances.

    • Phase 1 involves 20 to 100 healthy volunteers to evaluate safety and common side effects of the vaccine.

    • Phase 2 involves several hundred volunteers to gather information on safety, vaccine dosing, and ability to stimulate an immune response.

    • Phase 3 involves several thousand volunteers and a longer time frame than the earlier studies. Along with safety and side effects, most Phase 3 studies focus on efficacy -- how well the vaccine works in clinical trials -- and compare people who have received the vaccine to those who receive a placebo (a shot without the real vaccine).  During these studies, neither the participants nor the study managers know who received the vaccine and who received the placebo until the end of the study. This phase provides the firmest scientific evidence possible showing the difference between people who have been vaccinated and people who have not been vaccinated for both safety and effectiveness.

  • People volunteer to take part in clinical research studies. All study volunteers must go through a process called informed consent that ensures they understand all of the risks and benefits of being in a study, and those volunteers are reminded that they may leave a study at any time without losing any of their rights or benefits. 

  • Each clinical trial emphasizes the safety of the vaccine on people. As the research moves through to the next phase, the group of volunteers becomes bigger to include more diversity in people and circumstances. 

  • A diverse group of people volunteered to participate in every phase of the clinical trials, including populations disproportionately impacted by COVID-19 due to generations of systemic inequities. For example, in Pfizer’s clinical trials, about 42% of volunteers identified as Asian, Black/African American, Hispanic/Latino/a, or Native American. About 37% of volunteers for Moderna’s trials identified as Asian, Black/African American, Hispanic/Latino/a, or other.

  • Once the clinical trials can demonstrate vaccine safety and effectiveness at an appropriate dose, the manufacturer applies to the FDA to license the vaccine so that it can be used in the general population. 

  • The FDA reviews all of the data from the phased clinical studies using rigorous protocols and procedures. The vaccine is not authorized or approved until the FDA can ensure the vaccine is safe and effective.

  • In emergencies, such as the current COVID-19 pandemic, vaccines can also be authorized through an Emergency Use Authorization (EUA). The FDA usually authorizes an EUA for a specific population. After receiving an EUA, the manufacturer continues monitoring clinical trials as well as gathering and analyzing data. With more data, the manufacturer can then submit to the FDA for a Biologic License Application (BLA) so that the vaccine is able to be used more widely than originally covered in the EUA.

  • For each vaccine authorized by the FDA, the Advisory Committee on Immunization Practices (ACIP) carefully reviews all available data about the vaccine from clinical trials and other studies and makes recommendations for vaccine use in the general public. Recommendations include groups that should and should not receive the vaccine, as well as the timing, volume, number, and spacing of doses in a vaccine series. 

  • The ACIP is an independent advisory committee that provides guidance on the best use of vaccines to the Centers for Disease Control and Prevention (CDC) and U.S. Department of Health and Human Services (HHS). 

  • Once ACIP recommendations have been reviewed and approved by the CDC and HHS, they are published in CDC’s Morbidity and Mortality Weekly Report (MMWR). The MMWR publication represents the final and official CDC recommendations for immunization of the U.S. population.

  • The FDA and CDC continue to closely monitor vaccine safety after the public begins using the vaccine. Both agencies have both longstanding and new safety systems in place for heightened monitoring of all COVID-19 vaccines. Learn more about the vaccine safety monitoring systems: 

    • CDC’s V-safe is a new smartphone-based, after-vaccination health checker for people who receive COVID-19 vaccines. Vaccine recipients can opt-in to receive text messages and web surveys from CDC on how to report health problems following COVID-19 vaccination. The system will also provide telephone follow-up to anyone who reports medically significant adverse events. The report will be submitted to the Vaccine Adverse Event Reporting System (VAERS) while keeping patient identity confidential. V-safe is now available in English, Korean, simplified Chinese, Spanish, and Vietnamese.

    • Vaccine Adverse Event Reporting System (VAERS) - VAERS is an early-warning system that collects and analyzes reports of any problems that happen after vaccination. Anyone can submit a report, including parents, patients, and health care professionals.

    • Vaccine Safety Datalink (VSD) - VSD is a collaboration between CDC and several health care organizations to monitor vaccine safety. The system analyzes healthcare information for over 24 million people to conduct studies about rare and serious adverse events after immunization. 

    • Post-licensure Rapid Immunization Safety Monitoring (PRISM) - PRISM is the FDA’s immunization safety monitoring program. PRISM actively monitors the safety of medical products using electronic health information from over 190 million people. 

    • Clinical Immunization Safety Assessment Project (CISA) - CISA is a collaboration between CDC and seven medical research centers to answer complex safety questions. CISA conducts clinical research studies to further understand vaccine safety and recommend prevention strategies for adverse events following immunization.

  • Vaccine recommendations may change if safety monitoring reveals new information about vaccine risks, such as a new serious side effect. The CDC, with the help of the Colorado Department of Public Health and Environment, will send safety alerts to health care providers. If necessary, the federal government may remove a vaccine from the market.

COVID-19 immunity

  • You will not be immediately protected from COVID-19 after receiving the vaccine. Studies show that it takes about two weeks after you’ve received your last required dose for your body to fully protect itself against illness.

  • It may be possible that someone who has been vaccinated against COVID-19 could develop a mild or asymptomatic infection and even possibly spread the virus to others. More studies are needed to determine this. So in the meantime, it is important to continue taking COVID-19 precautions. Continue wearing masks and practicing physical distancing. 

  • While no vaccine is 100% effective, Pfizer and Moderna have reported that their vaccines are about 95% effective.

  • Scientists are working to learn more about COVID-19 variants. Early research suggests that the currently authorized vaccines are effective against the variants, though perhaps to varying degrees depending on the strain. Learn more about the COVID-19 variants.

  • The protection someone gains from having an infection (called natural immunity) varies depending on the disease, and it varies from person to person. Because this virus is new, we don’t know how long natural immunity might last. Some early evidence—based on a small sample size of people—seems to suggest that natural immunity may only last a few months in some people.

  • Regarding vaccination, we won’t know how long immunity lasts until we have more data on how well it works over time.

  • Experts are trying to learn more about both natural immunity and vaccine-induced immunity of COVID-19. 

  • In addition, in order to get natural immunity, you would have to get infected with COVID-19 and that can come with many risks. Getting the vaccine lets you gain immunity without the risk of getting the disease.

  • Because the vaccines are not 100% effective, some people who are fully vaccinated against COVID-19 may still get sick.

  • Based on what we know about vaccines for other diseases and emerging COVID-19 vaccine data, experts believe that getting a COVID-19 vaccine will likely keep you from getting seriously ill, and may prevent any symptoms from developing, even if you do get COVID-19.

  • It may be possible that someone who has been vaccinated against COVID-19 could still develop an infection with or without symptoms and even possibly spread the virus to others. Until we know more, it is important to continue taking precautions, like wearing masks and practicing physical distancing, even after you have been vaccinated.

  • For more information about what you can do after vaccination, see the CDC’s When You’ve Been Fully Vaccinated: How to Protect Yourself and Others.

  • Stopping a pandemic requires using all the tools available to us. Vaccines are the first step in returning to a more normal life. Still, we need Coloradans to continue to follow  important public health guidance, like physical distancing and mask wearing, until a vaccine is widely available and used by Coloradans.

  • It is still possible that members of your household could get COVID-19 because they have not been vaccinated. Until all household members are fully immunized  (i.e. two weeks have passed since you received the last required dose), you will need to continue to follow critical public health guidance, including: wearing a mask in public, maintaining at least 6 feet physical distance from others not in your household, avoiding large crowds, washing your hands often and staying home when you are sick.

  • Distributing a COVID-19 vaccine to the entire state of Colorado will take time. Stay the course until you are able to get a vaccine.

  • If it has been at least two weeks since your family member received their last required dose of vaccine, and you are not at high risk of severe COVID-19, you may visit them indoors without needing to wear a mask or physically distance. 
  • If you are at high risk of getting very sick from COVID-19, you should wear a well-fitting mask, physically distance, and remain outdoors or in a well-ventilated space while visiting family members who have been vaccinated.

  • Community (or herd) immunity means that enough people have developed immunity to a disease (either naturally or through vaccination) that there is no longer a risk of community transmission or outbreaks.

  • Until we better understand COVID-19 immunity and how vaccination affects transmissibility, we won’t know the percent of people needed for community (or herd) immunity.

  • We may not see a dramatic reduction initially as it takes time to develop individual and community (or herd) immunity. The state will be closely monitoring the vaccine’s effect on the number of new COVID-19 cases in Colorado. 

  • Until we know more, we still need all Coloradans to do their part to prevent the spread of the virus. Wear a mask, keep 6 feet of distance from others who don’t live with you, avoid gatherings, wash your hands often, and stay home when you are sick.

Protecting others after getting the vaccine

  • For most people, if a full two weeks have passed since your last required dose of the vaccine, you do not need to quarantine if you have no COVID-like symptoms -- but you should still wear a mask and physically distance while in public or at work. The exception is if you live in a congregate setting (such as a correctional facility or homeless shelter). In that case, you should still quarantine and get tested after exposure even after you are fully vaccinated. This is because residents of congregate settings may face high turnover, a higher risk of transmission, and challenges in maintaining recommended physical distancing.

  • If you work in a congregate setting or other high-density workplace and have no COVID-like symptoms, you do not need to quarantine following an exposure. However, CDC recommends getting tested after exposure and following through with any routine workplace screening programs, if applicable. 

  • If it has been less than two weeks since your final dose of the vaccine, you should quarantine if you think you have been exposed to COVID-19.

  • Whether or not you are in quarantine, watch for symptoms in the 14 days after exposure and get tested if you start to develop symptoms. If you test positive, you will need to isolate

  • Note that PCR test results will not be affected by the vaccine. A positive PCR test generally indicates recent COVID-19 infection.

  • Yes. If you develop COVID-19 symptoms at any time after being fully vaccinated, you should isolate and contact your health care provider for instructions on whether to be tested for COVID-19 or other infections.
  • If you experience the expected side effects after receiving a vaccine, it likely means that you are not contagious and do not need to isolate. Side effects typically occur one to two days after receiving the vaccine and can include fever, chills, headache, and fatigue. 
  • Cough, shortness of breath, nasal congestion, sore throat, or loss of taste or smell are not recognized side effects of the vaccine and may indicate COVID-19 infection (or another infection). 
  • Learn more about vaccine side effects in this FAQ. 

  • Yes, you should quarantine if you think you were exposed between doses of Pfizer or Moderna’s COVID-19 vaccines. If necessary, reschedule your second dose for after the quarantine period has ended.

  • Yes. If you develop COVID-19 symptoms between doses of a two-dose vaccine, you should isolate and contact your health care provider for instructions on whether to be tested for COVID-19 or other infections.
  • If you test positive for COVID-19, you may choose to get the second dose of your vaccine later as long as you have recovered from your infection and finished your isolation period.

Learn more about getting your second dose in this FAQ.

Vaccine laws and regulations

  • The state is not considering a COVID-19 vaccine mandate at this time.

  • Business owners cannot access a customer's protected health information, such as their COVID-19 immunization status. Customers may voluntarily share their vaccination status with the business if they choose to do so.

  • Every Coloradan’s immunization records are confidential, personal medical information that will never be shared publicly. The state will report information on the total number of residents who have been vaccinated in Colorado, but this data will not be attached to any individual’s personally identifying information.

  • The state health department maintains the Colorado Immunization Information System (CIIS), a confidential, population-based, secure computerized system that collects and consolidates individual-level vaccine and exemption data for Coloradans of all ages from a variety of sources.

  • Under Colorado law, you can choose to remove your immunization information from CIIS at any time. This is called an opt-out.

  • Coloradans are encouraged to handle their vaccine cards with care. If a vaccine card gets lost or destroyed, you can contact the provider where you received your vaccine to ask for your immunization record.

  • If you received your vaccine in Colorado, you can also request complete immunization records for yourself or your child by reaching out to the Colorado Immunization Information System (CIIS) Help Desk at 303-692-2437. Because CIIS records are confidential medical information, the state requires a notarized Request to Release Immunization Record form, along with a clear copy of a verifiable form of identification.

Emergency Use Authorization

  • In certain emergency situations, the Food and Drug Administration (FDA) may issue an Emergency Use Authorization to provide more timely access to critical medicines when there are no other options available. An Emergency Use Authorization permits the FDA to allow medical products that have met certain criteria, to treat, diagnose, or prevent serious or life-threatening diseases to be used.

  • Watch this short video from the FDA about Emergency Use Authorization.

  • EUAs were initially introduced in 2004 to prepare for bioterrorism attacks. Under an EUA, the government is able to authorize medical treatments and products in the event of a Chemical, Biological, Radiological, and Nuclear (CBRN) attack.

  • The FDA may issue an EUA for a medical product if it meets the following criteria:

    • The disease or CBRN agent in question can cause a serious or life-threatening illness or condition. 

    • There is reasonable belief, after looking at all the scientific evidence, that the product may be effective for its intended use. The phrase “may be effective” lowers the standards for scientific evidence typically required for FDA approvals.

    • The known and potential benefits outweigh the known and potential risks. The FDA will look at all available scientific evidence to determine the risk and benefits of a product. 

    • There is no adequate, approved, and available alternative to the product.

  • Besides the currently authorized COVID-19 vaccines, the only vaccine that has been authorized under an EUA so far was an anthrax vaccine in 2005. This vaccine was given to certain military personnel who were at heightened risk of exposure to anthrax.

  • Although not common, EUAs have been issued multiple times in the past for tests, treatments, and medical equipment.  

    • In 2009, EUAs were issued for diagnostic tests, personal protection equipment, and certain antiviral drugs during the H1N1 Swine Influenza pandemic.  

    • In 2013, EUAs were issued for diagnostic tests related to H7N9 influenza and Middle East Respiratory Syndrome (MERS). 

    • Several EUAs have already been issued for some COVID-19 tests and treatments, for example the antiviral medication remdesivir (recently approved), convalescent plasma, and multiple COVID-19 tests.