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FAQ: COVID-19 VACCINES & CLINICAL TRIALS 

FREQUENTLY ASKED QUESTIONS ABOUT THE COVID-19 VACCINES AND CLINICAL TRIALS

Note: To find a vaccination site, click here.

HOW DO THE COVID-19 VACCINES WORK? 

The COVID-19 vaccines are a type of medicine that work by teaching our body how to recognize and fight the virus that causes COVID-19. The COVID-19 vaccines will help protect us from getting COVID-19 or getting severely sick with the virus. The COVID-19 vaccines are a powerful tool that will help end the pandemic and help us get back to the moments we miss the most.  

WHAT ARE THE COVID-19 VACCINES CURRENTLY AVAILABLE? 

As of February 27, 2021, there are three COVID-19 vaccines that have received authorization for emergency use by the US Federal Food and Drug Administration (FDA). They are:

  • The Pfizer-BioNTech COVID-19 vaccine, approved on December 11, 2020.

  • The Moderna COVID-19 vaccine, approved on December 18, 2020.

  • The Johnson & Johsnon COVID-19 vaccine, approved on February 27, 2021.

WHAT’S HAPPENING WITH THE JOHNSON & JOHNSON VACCINE? 

The CDC and the FDA recommended a pause in use of the Johnson & Johnson vaccine after six women ages 18-48 reported a rare, but severe blood clot six to 13 days after receiving the vaccine.  

These cases are currently being investigated by the CDC and the FDA in order to ensure that the vaccine is safe for the public. 

If you received the J&J vaccine more than a month ago, the risk of experiencing a blood clot  from it is very low. If you received the vaccine within the past couple weeks, your risk of developing a blood clot is also very low; however, please continue to monitor your symptoms.  

If you experience any of these symptoms, reach out to your health care provider immediately. 

  • Severe headache

  • Backache

  • New neurologic symptoms

  • Severe abdominal pain

  • Shortness of breath

  • Leg swelling

  • Tiny red spots on the skin (petechiae)

  • New or easy bruising

It’s also important to note that while the J&J vaccine currently is unavailable, there are two vaccines that still are available– Pfizer's and Moderna’s.  

ARE THERE OTHER VACCINES ON THE WAY? 

Yes, as of December 28, 2020, large-scale clinical trials are planned or underway for two COVID-19 vaccines in the United States: 

  • AstraZeneca’s COVID-19 vaccine

  • Novavax’s COVID-19 vaccine

WHY ARE THERE SO MANY COVID-19 VACCINES IN DEVELOPMENT? 

There are seven billion people in the world and COVID-19 has impacted every country on every continent. This means we need to have multiple vaccines to have COVID-19 under control. Also, given the diversity of our communities, having multiple vaccines is a good approach to increase our chances of finding more than one vaccine that is safe and that works for everyone. 

WHAT IS THE PROCESS OF DEVELOPING A COVID-19 VACCINE? 

The process of making the COVID-19 vaccines and the ones underway involves rigorous testing in thousands of participants in clinical studies. Once there is enough information, the U.S. Food and Drug Administration (FDA) determines risks and benefits and recommends or denies the approval of the vaccine before the vaccine reaches the public. The FDA is the agency responsible for ensuring the safety and effectiveness of the COVID-19 vaccines in the United States. The COVID-19 vaccines currently available received authorization by the FDA for emergency use based on clinical testing and guidelines to ensure the vaccines are safe to use. Now that we have three COVID-19 vaccines available, the FDA will continue to monitor and track side effects as it normally does with new vaccines. 

HOW DO I KNOW THE COVID-19 VACCINES ARE SAFE AND EFFECTIVE, GIVEN HOW QUICKLY THE VACCINES ARE BEING DEVELOPED? 

Both the FDA and the CDC ensure that the recently authorized COVID-19 vaccines for emergency use, and those underway are safe and effective for our community. The FDA and the CDC carefully evaluate that all vaccines are as safe as possible, and because vaccines are given to millions of people to prevent serious diseases, they’re held to very high safety standards. As mentioned, the COVID-19 vaccines undergo rigorous testing that includes vaccinating tens of thousands of people who participate in clinical studies to generate the information needed for the FDA to determine their safety and how well they work. After the FDA authorizes a COVID-19 vaccine for emergency use, the CDC then reviews the COVID-19 vaccine available information before giving recommendations for public use. Even after the COVID-19 vaccines are approved, the FDA continues to monitor public safety. 

WHAT ARE THE COMMON SIDE EFFECTS OF THE COVID-19 VACCINES? 

Sometimes people might feel under the weather for 1-2 days after receiving either of the COVID-19 vaccines currently available. This is totally normal. The most common side effects are very similar to the side effects seen with most vaccines. This include a sore arm where you got the vaccine, fevers, and tiredness within three days after receiving a vaccine. These side effects usually mean that the vaccine is working to build the immunity we need to recognize and fight COVID-19. If you don’t have side effects, that’s normal as well, the COVID-19 vaccine is still working.  

For the Pfizer and the Moderna vaccine that require a second dose, some people may feel side effects for a few days after either or both doses. 

Here is a list of common short-term side effects for the COVID-19 vaccines that should eventually go away: 

  • Pain, redness, and swelling in the arm where you got the vaccine

  • Fatigue or tiredness

  • Headache

  • Muscle aches or pains

  • Chills

  • Fever

  • Nausea

Similar side effects have been reported for the Johnson & Johnson vaccine, and like the Pfizer and Moderna COVID-19 vaccine, these side effects usually start within a day or two of getting the vaccine, but they go away in a few days.  

If you have questions about symptoms or any other side effects after you receive a COVID-19 vaccine, ask your health care provider. 

You can also download v-safe in your smartphone. V-safe is a tool that checks in on you after your COVID-19 vaccination.  

WHO WILL GET THE COVID-19 VACCINES FIRST? 

As of December 22, 2020, the CDC has provided the following COVID-19 vaccine rollout recommendations.  

Under phase 1a, the COVID-19 vaccines are currently available for: 

  • Health care personnel

  • Residents of long-term facilities

Under phase 1b, the priority groups recommended to receive the COVID-19 vaccines next are: 

  • Frontline essential workers like fire fighters, police officers, correction officers, food and agricultural workers, USPS workers, manufacturing workers, grocery store workers, and those who work in the educational sector (teachers, support staff, and daycare workers)

  • People aged 75 years and older

Under phase 1c, the priority groups recommended to receive the COVID-19 vaccines next are:  

  • People aged 65-74 years due to their higher risk of hospitalization, illness, and death from COVID-19

  • People aged 16-64 years with underlying medical conditions

  • Other essential workers who work in transportation and logistics, food service, housing construction and finance, information technology, communications, energy, law, media, public safety, and public health.

Although the CDC provides recommendations on who should get the COVID-19 vaccine next, states ultimately have the final say. Search for your local health department in your area here for more information. 

WHY IS IT IMPORTANT TO GET A COVID-19 VACCINE ONCE IT’S AVAILABLE TO ME?  

Getting vaccinated is a powerful tool that will help save lives and end the pandemic. When more of us are protected, we can get back to sharing those moments we have missed the most during this time. 

WHEN CAN MOST ADULTS GET VACCINATED AGAINST COVID-19? 

On March 11, 2021, the Biden Administration directed all states to make all adults eligible to receive the COVID-19 vaccines no later than May 1, 2021. In the meantime, each state determines who, when, and where in terms of vaccine distribution. As vaccine availability increases, vaccination recommendations will expand to include more people. 

Ask your local health department for up-to-date information. Search for your local health department in your area here.  

WHERE CAN I GET ONE OF THE COVID-19 VACCINES ONCE IT IS MY TURN? 

At the moment each state is managing its own rollout. You can visit this website to find your local health department and vaccination sites near you and learn when it is your turn to get vaccinated in your state. 

You can also use Vaccine Finder, a free online service where you can search for pharmacies and providers that offer vaccination. Information about where COVID-19 vaccines are available is updated daily. Click here to find COVID-19 vaccines in your area.   

WILL MY LOCAL PHARMACY OFFER THE COVID-19 VACCINES? 

At the moment, some retail local pharmacies have started distribution of the Pfizer, the Moderna, and Johnson & Johnson COVID-19 vaccines with state-specific eligibility requirements. For updates on additional locations near you, visit the following retail pharmacy websites, in addition to your local grocery store pharmacies:  

You can also use Vaccine Finder to search for more local pharmacies that offer vaccination in your community. 

DO I NEED HEALTH INSURANCE TO RECEIVE ONE OF THE COVID-19 VACCINES? 

No, the COVID-19 vaccines are free for everyone in the United States whether you have insurance or not. However, your insurance company or state’s relief fund will be billed a fee for the vaccine administration. Be sure to bring your insurance card with you if you have health insurance. If you do not have health insurance, you can still get the vaccine. 

CAN I GET A COVID-19 VACCINE IF I’M PREGNANT OR BREASTFEEDING? 

Most experts say that pregnant or breastfeeding women should have a personal discussion with their health care provider to make a health decision that is best for them. Please contact your health care provider to find out if you should get the vaccine while pregnant or breastfeeding. 

CAN I GET A COVID-19 VACCINE IF I’VE HAD COVID-19? 

Yes. Even if you had COVID-19 before, you can still get one of the vaccines. We still don’t know how long natural immunity to COVID-19 lasts, and it’s important to protect ourselves and our loved ones. Some studies suggest that it is possible to get COVID-19 twice. The recommendation is to wait at least four weeks after full recovery from COVID-19 infection to get the COVID-19 vaccine. 

After getting the COVID-19 vaccine you should continue to wear a mask, avoid large crowds and indoor gatherings in public spaces, and wash your hands often. 

CAN I GET A COVID-19 VACCINE IF I AM UNDOCUMENTED? 

Yes, the COVID-19 vaccines are available for the undocumented community. Public health employees should not discriminate against undocumented individuals from getting the COVID-19 vaccines. Also, the Biden administration has stated that ICE and CBP will not be at vaccination sites. Some personal information might be requested to receive the COVID-19 vaccine, and the personal information requested will vary by site, but rest assured that this information is kept private and will not be shared with other entities. We understand that fear is a reality for the undocumented community when giving out their personal information, so if you have concerns about sharing personal information, speak to allies or a local trusted source in your community. You can also visit www.immigrationlawhelp.org for additional resources. 

IF I AM TAKING OTHER MEDICATIONS, CAN I GET ONE OF THE COVID-19 VACCINES? 

Always seek the advice of your health care provider with any questions you may have regarding your medications while receiving the COVID-19 vaccine and if you have any medical contraindications to any of the COVID-19 vaccines. 

IF I HAVE A CHRONIC CONDITION, LIKE DIABETES OR HEART DISEASE, CAN I GET ONE OF THE COVID-19 VACCINES? 

Living with a chronic condition increases the risk of getting very sick from COVID-19, so yes, it is generally recommended to get a COVID-19 vaccine. However, if you have a chronic or underlying medical condition, it’s best to have a conversation with your health care provider to make a decision that is right for you. Make sure to also check your local health department’s website as it may already be your turn to get vaccinated. You can visit this website to find your local health department. 

CAN I CHOOSE WHICH COVID-19 VACCINE TO GET? 

Vaccine availability may be limited, and it might be difficult to choose which vaccine to get. All COVID-19 vaccines that have been approved are highly effective. Once we have access to a COVID-19 vaccine, it is important we get the vaccine that is available to us at the time of eligibility. 

HOW OFTEN WILL I NEED TO GET VACCINATED AGAINST COVID-19? 

Currently, we do not know how long protection from a given vaccine will last. The virus is changing or mutating, which may make re-vaccination necessary. Also, each COVID-19 vaccine will have its own unique schedule depending on how long protection or immunity will last. Public health experts are keeping a close eye on the virus to learn more about how long the COVID-19 vaccines will protect us once we get vaccinated. 

DO THE COVID-19 VACCINES CONTAIN THE LIVE VIRUS THAT CAUSES COVID-19? 

No, the recently authorized COVID-19 vaccines and the COVID-19 vaccines currently in development do not contain the live virus that causes COVID-19 so it cannot give us COVID-19 or transmit the virus. As mentioned, the COVID-19 vaccine is a type of medicine that will teach our body to build the mechanisms needed to recognize and fight the virus if we become exposed. 

WHAT ARE THE COVID-19 VACCINES MADE OF? 

The Pfizer and the Moderna COVID-19 vaccines use messenger RNA also called mRNA. mRNA COVID-19 vaccines teach our body to recognize and fight the virus that causes COVID-19, protecting us from getting sick all together or getting too sick. mRNA does not interact or change our DNA and mRNA COVID-19 vaccines do not contain any live virus so you cannot get sick with COVID-19 from these vaccines. To learn more, click here.  

The Johnson and Johnson COVID-19 vaccine does not use messenger RNA, instead it uses a viral vector to create a strong immune response in our body that will recognize and fight the virus that causes COVID-19. Like messenger RNA vaccines, the viral vector in the Johnson & Johnson COVID-19 vaccine does not interact or change our DNA and does not contain any live virus so you cannot get sick with COVID-19 from this vaccine. To learn more, click here.   

HOW DOES MODERNA’S VACCINE COMPARE TO PFIZER’S? 

Both vaccines use the messenger mRNA technology which will teach our body to fight a COVID-19 infection in two ways. First, by recognizing the virus, and second, by fighting the virus. Both the Pfizer and Moderna vaccines offer excellent protection against COVID-19. The Pfizer is authorized by the FDA for people aged 16 and older. Moderna’s is for people 18 years and older. Both the Moderna and the Pfizer/BioNTech vaccines require two vaccine doses. The interval between Moderna doses is 28 days, and the interval for the Pfizer vaccine is 21 days. Additionally, Moderna’s vaccine has logistical advantages including that it can be stored in most regular freezers, which makes it easier to distribute. 

WHY DO I NEED A SECOND DOSE OF THE PFIZER AND THE MODERNA COVID-19 VACCINES? 

Both the Pfizer and Moderna vaccines require two doses for them to be most effective. The first dose helps our body recognize the virus and gets our immune system ready, while the second dose strengthens that immune response. Our immunity will be much higher after the second dose, because our body will be more prepared to fight COVID-19. It’s important to keep your appointment for the second dose to be fully protected. 

CAN I TAKE THE PFIZER DOSE AND THEN LATER THE MODERNA OR OTHER COVID-19 VACCINE IN THE SECOND ROUND? 

No, the current recommendation is to take two doses of the same vaccine provider. For example, if you receive the Moderna COVID-19 vaccine for the first dose, make sure to receive the Moderna COVID-19 vaccine for the second dose. It is important to stick with one vaccine from one provider. Remember to save the name of the COVID-19 vaccine you receive for when you get the second dose. Ask your health care provider who is administering the vaccine to give you a record. 

If you receive the Johnson & Johnson COVID-19 vaccine, this is a one dose vaccine, so you do not need to return for a second dose. After one dose, you will be fully vaccinated with the Johnson & Johnson vaccine.  

WHAT DO I NEED TO KNOW ABOUT THE NEW JOHNSON & JOHNSON COVID-19 VACCINE? 

The Johnson & Johnson vaccine is a one dose vaccine that works similarly to the Pfizer and Moderna vaccines. As explained earlier, the Johnson & Johnson COVID-19 vaccine is a viral vector vaccine that creates a strong immune response that will help our body fight the virus that causes COVID-19. It meets the same safety, quality, and effectiveness standards of the FDA and received authorization for emergency use by the FDA on February 27, 2021. Just like the Moderna and Pfizer vaccines, the Johnson & Johnson vaccine is very effective at preventing severe illnesses, hospitalizations, and death due to COVID-19. It’s important to note that you cannot get COVID-19 from any of the COVID-19 vaccines currently available.  

ARE THE CURRENT COVID-19 VACCINES APPROVED FOR CHILDREN? 

Not at the moment. Currently, the Moderna and Johnson & Johnson vaccines are approved for people 18 and older, and the Pfizer vaccine is approved for people 16 an older. We still don’t know when the COVID-19 vaccines will be approved for children, but we do know that Pfizer and Moderna is performing studies on their vaccines in 12 to 17-year olds in clinical trials. 

WILL I HAVE TO FOLLOW OTHER PREVENTION MEASURES AFTER I RECEIVE A COVID-19 VACCINE? 

Yes, after receiving a COVID-19 vaccine, we should continue to wear masks, practice physical distancing, and wash hands with soap and water for at least 20 seconds. These are some of the steps we can continue to follow to slow the spread of the virus in our community after we have been vaccinated. This is especially important to protect family members and friends who are waiting to get vaccinated. Keep in mind that one tool alone is not going to stop the COVID-19 pandemic. We will need a combination of different tools to stop COVID-19 transmission. To learn more about guidelines after you have been fully vaccinated, click here.  

WHAT HAPPENS IF I DON’T GET VACCINATED AGAINST COVID-19? 

Vaccination in the U.S. is voluntary. It is a personal decision. If you have the opportunity to get vaccinated, it will help protect you from getting COVID-19 or getting severely ill with the virus. It will also contribute to greater immunity and fewer cases in your community and across the country. This will help end the pandemic sooner and getting back to some of the things we miss the most.  

DO THE COVID-19 VACCINES IMPACT FERTILITY? 

There is no current evidence that the COVID-19 vaccines impact someone’s fertility or someone’s ability to get pregnant. More tests are underway to determine how the COVID-19 vaccines affect people who are pregnant, breastfeeding, or trying to become pregnant. Make sure to talk with your health care provider about your unique situation and options. 

WHAT CAN WE ALL DO TO TACKLE MISINFORMATION AROUND THE COVID-19 VACCINES? 

We encourage you to share resources from trusted sources in your community with your friends, neighbors, and family to ensure that they also have the latest information about COVID-19 vaccines. Here are a couple of resources you can check out:  

  • You can talk to your health care provider and consult official government sources such as govor your local health department to help you start conversations with your loved ones about the COVID-19 vaccines.

WHAT ARE CLINICAL TRIALS? 

Clinical trials are science-based studies performed in people to test safety and effectiveness of a new medication, treatment, screening, vaccine, and more. It is important to note that before entering the clinical development, an investigational vaccine has previously been studied to make sure it is safe to test on humans. There are three phases to the clinical development for a new vaccine to be approved. You can click here for a visual of the three phases on how a new vaccine is developed, approved, and manufactured. 

WHY DO CLINICAL TRIALS SOMETIMES PAUSE DURING THE CLINICAL DEVELOPMENT? 

At any moment during the clinical development, if scientists observe concerning side effects, they can put the clinical trial on pause and it is only after a detailed investigation when scientists decide to continue or abandon the clinical trial. Pausing clinical trials during the clinical development is common and they have and will continue to occur during the development of more COVID-19 vaccines. These pauses are only signs that scientists are following protocols to ensure safety. 

WHY IS OUR PARTICIPATION IMPORTANT IN CLINICAL TRIALS? 

Historically, people who are Latino, Black, Native American/Alaskan Native, and people from other racial and ethnic minority groups, which are also communities disproportionally impacted by the COVID-19 pandemic, have been significantly underrepresented in health research. For this reason, public health experts are making a call to action to ensure that people from racial and ethnic minority groups become part of clinical trials for the COVID-19 vaccines. Those who have participated in clinical trials say their motivation is to help advance health care and contribute to scientific findings for the collective good. 

WHERE CAN I FIND A CLINICAL TRIAL FOR THE COVID-19 VACCINES?  

Our colleagues at COVID-19 Prevention Network have created a participant screening registry for potential participants who want to partake in current or future COVID-19 prevention clinical trials. Please note that each trial is at different phases of recruitment, so information will vary. If you are interested in taking part of the registry, click here to begin the survey and you could become part of clinical trials currently looking for participants. The survey typically takes 10 minutes to complete. 

The National Institutes of Health’s Community Engagement Alliance Against COVID-19 Disparities (CEAL Alliance) also aims to ensure that COVID-19 prevention and treatment clinical trials include racially and ethnically diverse communities most affected by the pandemic. The CEAL Alliance conducts outreach and seeks input from communities to raise awareness about COVID-19 and to address misinformation and mistrust about the pandemic in efforts to combat it. The CEAL Alliance research teams are working to expand community outreach efforts by NIH COVID-19 trial networks while engaging with trusted organizations and people. For more details, click here.   

WHERE DO I FIND ADDITIONAL RESOURCES?  

Webpages: 

Infographics: 

Fact Sheets: 

Social Media Toolkits: