COVID-19 Vaccine frequently asked questions

Last updated August 27, 2021.

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Vaccination bottles

Top 10 most frequently asked questions

  • There are hundreds of vaccine providers throughout the state. Here are some ways to find a vaccine near you:

    • Visit our vaccine finder page for a map and list of providers. Many providers take walk-ins. You can contact any provider directly for more information.

    • Check your local pharmacy or participating Walmart, Sam’s Club, Safeway, Cardinal, City Market/King Soopers, and Costco locations.

    • The state-run mobile COVID-19 vaccination clinics are now making stops in all four corners of the state. You can book an appointment online.

    • Local public health agencies are organizing pop-up clinics all over the state with different community partners. Visit your local public health agency’s website or social media channel for more information about community clinics in your area.

    • 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) Monday through Friday, 8 a.m. to 8 p.m.; Saturday and Sunday, 9 a.m. to 6 p.m. MT. Multiple languages are available.

  • All authorized COVID-19 vaccines are going through the most intense safety monitoring in U.S. history. 
  • Millions of people in the United States have safely received a vaccine and are now protected from COVID-19.
  • Tens of thousands of people volunteered to help test the vaccines in clinical trials. These clinical trials showed that the vaccines are safe and work well. The vaccines met the Food and Drug Administration’s (FDA) rigorous scientific standards for safety, effectiveness, and quality.
  • Learn more about vaccine safety.
     

  • Read the CDC’s current guidance for mask-wearing after vaccination.
  • Masks are required in certain public indoor spaces, even for fully vaccinated people. Learn more about where you need to wear a mask in Colorado on CDPHE’s mask guidance webpage.
  • If you are fully vaccinated and you have been exposed to someone with suspected or confirmed COVID-19, you should wear a mask indoors in public for 14 days following exposure or until your test result is negative. You should also get tested three to five days after exposure, even if you don’t have symptoms.
  • People are considered fully vaccinated: 
    • Two weeks after their second dose in a two-dose series, like the Pfizer or Moderna vaccines. 
    • Two weeks after a single-dose vaccine, like Janssen’s (Johnson & Johnson) vaccine.
  • If you have a condition or are taking medications that weaken your immune system, you may NOT be fully protected even if you are fully vaccinated. Talk to your healthcare provider. Even after vaccination, you may need to continue taking all precautions.
  • Learn more about how to protect yourself in this FAQ.

  • No. The vaccines don’t contain the COVID-19 virus, and it is not possible to get COVID-19 from a vaccine.

  • 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.

  • Yes. We recommend that you get a vaccine even if you previously had COVID-19.

  • Scientists are still learning more about how long you might be immune 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.

  • If you had COVID-19, CDC says you may wait a few months after your infection before getting the vaccine. It’s unlikely that you will get COVID-19 again 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. 

  • Learn more about immunity in this FAQ. 

  • Yes, the vaccine is free. Providers should not ask you to pay for the vaccine or other administrative costs,  even if you don’t have health insurance.

  • If you do have insurance, your provider may seek reimbursement from your health insurance company, 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 you have one.

  • 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) Monday through Friday, 8 a.m. to 8 p.m.; Saturday and Sunday, 9 a.m. to 6 p.m. MT. 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.

  • 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) Monday through Friday, 8 a.m. to 8 p.m.; Saturday and Sunday, 9 a.m. to 6 p.m. MT. Multiple languages are available.

  • Learn more about getting the vaccine in this FAQ.

  • In developing vaccines 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 are always 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.

  • Yes. People who are fully vaccinated are protected from the Delta variant. 

  • Getting vaccinated also protects others around you. Current data suggests that vaccination reduces the spread of infection, leading to fewer opportunities for new variants to develop and spread.

  • Yes. Children age 12 to 17 are recommended to get the Pfizer COVID-19 vaccine. Clinical trials showed that the Pfizer vaccine is safe and extremely effective in this age group.

  • Side effects for children were about the same as for adults. 

  • While children are less likely to get seriously sick or die from COVID-19 than adults, they are still at risk and can spread the virus to others. Vaccinating tweens and teens — especially before summer camps and back-to-school — will help keep kids safe through the end of the pandemic.

Frequently Asked Questions by topic

Getting a COVID-19 vaccine

  • Three COVID-19 vaccines are available: Pfizer, Moderna, and Janssen (Johnson & Johnson). The U.S. Food and Drug Administration (FDA) has authorized these vaccines for emergency use.

  • The Pfizer vaccine is available for people age 12 and older. The Moderna and Janssen vaccines are available for adults age 18 and older.

  • On August 23, 2021, the FDA fully approved the Pfizer vaccine for people age 16 and older.

    • The Pfizer vaccine will now be called Comirnaty (pronounced “koe-mir’-na-tee”).

    • While Pfizer’s Comirnaty vaccine is the first COVID-19 vaccine to receive full approval, all available COVID-19 vaccines have been shown to be safe and effective.

    • The Pfizer vaccine is still available for people age 12 to 15 under the FDA’s emergency use authorization.

  • The CDC has detailed information for each vaccine on their Different COVID-19 Vaccines page.

  • No. None of the vaccines is recommended over the other for adults 18 and over. Children age 12 to 17 can currently only get the Pfizer vaccine. 

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

  • The state of Colorado does not require minors to be accompanied 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.

  • Some vaccine providers may require children age 12 to 17 to have a parent or guardian with them at their appointment. We recommend calling your provider ahead of time to check whether they require parental accompaniment.

  • Not at this time. The Pfizer vaccine is authorized for people who are age 12 and older. The Moderna and Janssen (Johnson & Johnson) vaccines are authorized for adults 18 and up. Anyone younger than 12 years old should not get a vaccine unless they are enrolled in a clinical trial. 

  • Any vaccine use for younger children would only come after appropriate clinical trials and authorization by the FDA. We will continue to monitor clinical trials currently underway with the goal of making a COVID-19 vaccine available for younger 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. 

  • The Pfizer and Moderna vaccines are not meant to be 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.

  • People who have a moderately to severely compromised immune system may benefit from an additional dose of mRNA vaccine to make sure they have enough protection against COVID-19. Studies show that some people who are immunocompromised don’t build adequate levels of protection after receiving two doses of mRNA vaccines.
  • People who are recommended to receive an additional dose include people who have:
    • Been receiving active cancer treatment for tumors or cancers of the blood.
    • Received an organ transplant and are taking medicine to suppress the immune system. 
    • Received a stem cell transplant within the last two years or are taking medicine to suppress the immune system. 
    • Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome). 
    • Advanced or untreated HIV infection. 
    • Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response.
  • The additional dose should be the same vaccine product as the first two doses. However, an alternate mRNA dose can be used if that vaccine is not available.
  • Coloradans may self-report their moderate to severe immunocompromising conditions to vaccine providers in order to get an additional dose.

  • 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.

  • COVID-19 vaccines and other vaccines may now be given at the same time, if needed, or close together. 

  • Your doctor may consider the types of vaccine, whether you are behind on recommended vaccines, and what kind of side effects the vaccines may have before deciding whether or not to give them together. Talk to your doctor about additional concerns you might have about getting more than one vaccine at the same time.

  • Mile High United Way’s Ride United program is providing access to free rides (up to 25 miles each way) to vaccination sites across Colorado. Dial 2-1-1 or visit 211colorado.org to learn more.

  • Uber and Lyft are offering free rides to vaccine provider locations. Use your smartphone to book a ride on the  Uber and Lyft apps.

  • As part of President Biden’s National Month of Action initiative, some child care centers are offering free child care for people getting vaccinated.

  • KinderCare and Learning Care Group are offering free child care to help parents and caregivers get vaccinated and recuperate. Call KinderCare at (866) 337-3105 or Learning Care Group at (833) 459-3557 for more information.

  • Bright Horizons is offering free child care for workers at participating organizations while they get vaccinated and recover from side effects.

  • Many YMCA locations are also offering free child care during vaccination appointments. Contact your local YMCA for more details.

  • You can call 1-877-COVAXCO (1-877-268-2926) and an agent can help you register for an in-home vaccination. The call line is available Monday through Friday, 8 a.m. to 8 p.m.; Saturday and Sunday, 9 a.m. to 6 p.m. MT. and in multiple languages. If you are unable to make the call, a caregiver, family member, or friend can call on your behalf. 
  • Know that arranging an in-home vaccination will take time to coordinate and the visit may be longer than if you got the vaccine through another site.

  • The vaccine is free. Providers should not ask you to pay for the vaccine or other administrative costs, even if you don’t have health insurance. If you do have insurance, your provider may seek reimbursement from your health insurance company, but you should not be charged.

  • Providers are not allowed to turn you away, even if you don’t have health insurance. Medicare, Medicaid, and private insurance are required to cover the cost of the COVID-19 vaccines. If you do not have health insurance or your health insurance does not cover vaccine administration fees, providers may seek reimbursement for your appointment through the Provider Relief Fund or the COVID-19 Coverage Assistance 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 have one.

  • If a provider demands 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) Monday through Friday, 8 a.m. to 8 p.m.; Saturday and Sunday, 9 a.m. to 6 p.m. MT. 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.

  • 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.

  • No. 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 by filling out the following form: covid19.colorado.gov/VaccineConcerns. You can also call 1-877-COVAXCO (1-877-268-2926) Monday through Friday, 8 a.m. to 8 p.m.; Saturday and Sunday, 9 a.m. to 6 p.m. MT. Multiple languages are available.

No. You do not need to be a full-time resident of Colorado, nor of a particular Colorado county, to be vaccinated in Colorado.

  • No. 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.

  • Make every effort to receive the second dose of your COVID-19 vaccine exactly 21 days after the first dose of Pfizer and 28 days after the first dose of 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 up to 42 days after the first dose. The second dose can also be given up to four days early. 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. 

  • 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.

  • Under Colorado’s Healthy Families and Workplaces Act (HFWA), you are entitled to paid sick leave from your employer to recover from side effects. 

  • 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 be signs of COVID-19 infection (or another infection). If you feel any of these symptoms, begin isolating and get tested for COVID-19 as soon as you can.

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

  • No. Getting vaccinated won’t give you a positive test result. If you test positive shortly after being vaccinated, it’s likely that you caught COVID-19 before you were able to build immunity from the vaccine. Follow instructions on how to isolate until you feel better.

  • 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.

  • 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).

  • For more information, see CDC: What to Do If You Have an Allergic Reaction after Getting a COVID-19 Vaccine.

  • 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.

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

  • 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. 

  • The Johnson & Johnson vaccine is safe and effective in preventing COVID-19, and the benefits greatly outweigh the risks.

  • Serious side effects are extremely rare. There may be increased, but still rare, risks of an abnormal blood clotting disorder called thrombosis with thrombocytopenia syndrome (TTS) in women under age 50 or a nerve disorder called Guillain-Barre syndrome (GBS) in men over age 50.

  • CDPHE has sent information to health care providers to inform them about how to identify and treat TTS and GBS in the very rare case they were to occur.

  • 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 these extremely rare syndromes.

  • 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.

  • Yes. If you are trying to become pregnant now or want to get pregnant in the future, you may get a COVID-19 vaccine.

  • There is currently no evidence that COVID-19 vaccination causes any problems with pregnancy, including the development of the placenta. In addition, there is no evidence that fertility problems are a side effect of any vaccine, including COVID-19 vaccines. People who have received COVID-19 vaccines have gone on to get pregnant and have healthy babies.

  • Like all vaccines, scientists are studying COVID-19 vaccines carefully for side effects now and will continue to study them for many years.

  • Please talk with your doctor for more information if you have any concerns.

  • No. Your menstrual cycle cannot be affected by being near someone who received a COVID-19 vaccine. Individuals who have received a COVID-19 vaccine cannot shed any parts of the vaccine. 

  • Many things can affect menstrual cycles, including stress, changes in monthly schedule, problems with sleep, and changes in diet or exercise. Infections may also affect the menstrual cycle.

Health concerns and the vaccine

  • Yes. The best way to protect yourself and your baby from COVID-19 is to get vaccinated. There is now more evidence than ever about the safety and effectiveness of COVID-19 vaccination during pregnancy. The evidence suggests that the benefits of receiving a COVID-19 vaccine outweigh any known or potential risks of vaccination during pregnancy. For more information about the safety and effectiveness of COVID-19 vaccination during pregnancy, visit the CDC’s website.

  • Additional actions you can take to protect yourself include wearing a mask in public, keeping your distance from people who don’t live with you, washing your hands frequently, and limiting gatherings. These precautions are especially important if you live in an area where COVID-19 is spreading widely.

  • 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.

  • Yes. 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. Talk to your health care provider if you have additional questions.

  • People who have a moderately to severely compromised immune system may benefit from an additional dose of an mRNA vaccine to make sure they have enough protection against COVID-19. Studies show that some people who are immunocompromised don’t build adequate levels of protection after receiving two doses of mRNA vaccines.

  • More information can be found at CDC’s COVID-19 Vaccines for Moderately to Severely Immunocompromised People

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

  • 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, or Pfizer, or Janssen). 

  • If you have ethical concerns about the vaccines, we encourage you to talk to your faith leaders about them.

  • Yes. According to the American Red Cross and Vitalant, you can donate blood if you’ve received a COVID-19 vaccine manufactured by Pfizer, Modern, Janssen/J&J, Novavax, or AstraZeneca. You must also be symptom-free and fever-free to donate blood. 
  • Check with your local blood center for additional information.

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.

No. None of the currently authorized vaccines contain the 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.

  • Yes. Children age 12 to 17 are recommended to get the Pfizer COVID-19 vaccine. Clinical trials showed that the Pfizer vaccine is safe and extremely effective in this age group.

  • Side effects for children were about the same as for adults. 

  • While children are less likely to get seriously sick or die from COVID-19 than adults, they are still at risk, and can spread the virus to others. Vaccinating tweens and teens — especially before summer camps and back-to-school — will help keep kids safe through the end of the pandemic.

  • The Centers for Disease Control and Prevention (CDC) has studied reports of inflammation of the heart muscle and surrounding tissue, called myocarditis and pericarditis, after COVID-19 vaccination among younger people. They found this adverse event is extremely rare and very few people will experience it after vaccination. In the very rare case it does occur, most cases are mild, and people often recover on their own or with minimal treatment.

  • Myocarditis and pericarditis are much more common if you get COVID-19, and the risks to the heart from COVID-19 infection can be more severe. Therefore, CDC continues to recommend COVID-19 vaccination for everyone 12 years of age and older, given the greater risk of COVID-19 illness and possibly severe complications.

  • The Moderna and Janssen (Johnson & Johnson) vaccines are only available to adults 18 years of age and older.

  • 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, government agencies, philanthropic organizations, and pharmaceutical companies. 

    • 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. 

    • 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.

  • All authorized COVID-19 vaccines are going through the most intense safety monitoring in U.S. history.

  • Millions of people in the U.S. have safely received a vaccine and are now protected from COVID-19.

  • 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. Tens of thousands of people volunteered in these trials to help make sure the vaccines are safe and work well.

  • After the clinical trials, two independent advisory committees 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.

  • 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. 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, 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). 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 is much more likely to cause death than any COVID-19 vaccine. The CDC, FDA, and CDPHE recommend getting vaccinated as the best way to protect yourself from COVID-19.

  • A review of available clinical information, including death certificates, autopsy, and medical records, has not established a causal link between deaths and COVID-19 vaccines. 

  • CDC uses the Vaccine Adverse Event Reporting System (VAERS) to closely monitor reports of death following COVID-19 vaccination. 

  • 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. 

  • Reports of death following vaccination do not necessarily mean the vaccine caused the death. There are deaths every day from a variety of causes.

  • CDC follows up on any report of death to ask for more information. They use this information to learn more about what happened and to find out whether the death had something to do with the vaccine.

  • Over 273 million doses of COVID-19 vaccines were administered in the United States from December 14, 2020, through May 17, 2021. During this time, VAERS received 4,647 reports of death (0.0017%) among people who received a COVID-19 vaccine. 

  • Recent reports show that the J&J/Janssen COVID-19 vaccine may be associated with an extremely rare but serious kind of blood clot (called thrombosis with thrombocytopenia syndrome or TTS), which in very few cases has resulted in death.

  • These types of blood clots are extremely rare, occurring at a rate of about 9 per 1 million vaccinated women between 18 and 49 years old. For women 50 years and older and men of all ages, these types of blood clots are even more rare. Most people who developed this very rare type of blood clot recovered.

COVID-19 immunity

  • It takes two weeks after you’ve received your last required dose for your body to fully protect itself against illness.

  • Yes. All authorized COVID-19 vaccines work well to protect you from getting very sick, needing to be hospitalized, or dying from COVID-19.

  • People who are fully vaccinated may become infected with COVID-19. However, fully vaccinated people are much more likely to have mild cases of COVID-19 than unvaccinated people.

  • Learn more about COVID-19 variants.

  • In order to get natural immunity, you would have to become infected with COVID-19, which can come with many serious risks and complications. Getting the vaccine gives you protection without the risks of getting sick.

  • 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.

  • Yes. Because the vaccines are not 100% effective, some people who are fully vaccinated against COVID-19 may still get sick. However, the risk of getting sick -- especially severely sick -- is much lower if you are vaccinated.

  • 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.

  • 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.

  • While no vaccine is 100% effective, getting vaccinated greatly reduces your risk of COVID-19.

  • If you do get sick after being vaccinated, it is much less likely that your symptoms will be severe or that you will need to be hospitalized. The vaccines also greatly reduce the risk of death from COVID-19.

  • Based on the data, scientists believe that vaccinated people are much less likely to spread COVID-19 than unvaccinated people. Getting vaccinated doesn’t just protect you, but helps keep your family and community healthy as well.

  • 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 community (or herd) immunity. The state will be closely monitoring the vaccine’s effect on the number of new COVID-19 cases in Colorado. 

Protecting others after getting the vaccine

  • If you are fully vaccinated and you have been exposed to someone with suspected or confirmed COVID-19, you should wear a mask in public indoor spaces for 14 days after your exposure. You should also get a COVID-19 test three to five days after exposure. You can stop wearing a mask if you test negative.

  • 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 be signs of 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

  • You may be required as a condition of employment for some employers. But generally, employment aside, no, you aren’t required to get vaccinated at this time.

  • Yes. The federal Health Insurance Portability and Accountability Act (HIPAA) does not apply to businesses like retail stores and restaurants because these businesses do not engage in any form of health care activity. It is not a violation of any federal or state law for a business to ask customers about their vaccination status. Customers may voluntarily share this information with a business if they choose to do so. A business may require public health measures (e.g. mask-wearing) if a customer chooses not to share their vaccination status.  

  • The state public health department, which maintains the Colorado Immunization Information System (CIIS), does not share a person’s protected health information, such as their COVID-19 vaccination status, with any business. Individuals may choose whether to share their vaccination status with others.

  • 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.

  • Yes, they can. Questions regarding COVID-19 vaccination requirements for students, faculty and/or staff should be directed to the specific college or university.

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.