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We’ve compiled the following comprehensive list of common questions. It is not intended to be individual medical advice. If you have questions specific to your situation, contact your health care provider.

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For shorter overviews about COVID-19 vaccination, read our fact sheet in English and Spanish. Have a general question not addressed here? Email it to us at  

Last updated:  March 30, 2022


Safety/Side Effects

    • What are the benefits of getting a COVID-19 vaccine?


      COVID-19 can cause severe medical complications and lead to death in some people. There is no way to know how COVID-19 will affect you. If you get COVID-19, you could spread the disease to family, friends and others around you. 

      Getting a COVID-19 vaccine can help protect you by creating an antibody response in your body without your having to become sick with COVID-19.

      A COVID-19 vaccine might prevent you from getting COVID-19. Or, if you get COVID-19, the vaccine might keep you from becoming seriously ill or from developing serious complications.

      Getting vaccinated also might help protect people around you from COVID-19, particularly people at increased risk of severe illness from COVID-19.

    • How do we know a COVID-19 vaccine is safe?


      The U.S. has a long history of assuring vaccines are safe through the use of specific, detailed and time-tested protocols. Before any new vaccine is brought to market, it has been given to thousands of people under stringent monitoring for safety. Sometimes, very rare side effects are recognized only after the vaccine is licensed because they occur so infrequently, but such side effects are very rare and must be weighed against the good the vaccine will do.

    • How did the process for approving a vaccine move so quickly?


      Traditionally, it has taken many years to develop a vaccine, confirm its safety and efficacy, and manufacture the vaccine in sufficient quantities for public use. This timeline was substantially shortened for COVID-19 vaccines. There are several ways this was possible. First, some clinical trials combined phases 1 and 2 to assess safety and the immune responses. Second, because of the high number of new cases of COVID-19 in many places, differences in disease risk between those who received the vaccine and those who received the placebo or comparison vaccine were measured more quickly than in the absence of a pandemic. Third, the United States government and others heavily invested in building the manufacturing capacity to produce large numbers of vaccine doses before the findings of the phase 3 trials are available. Typically, vaccine manufacturers wait until the phase 3 trial is completed and shows safety and efficacy before making such a large investment in manufacturing capacity. None of these factors that contribute to the accelerated development of a vaccine for COVID-19 imply that safety, scientific or ethical integrity were compromised, or that short-cuts were made.

    • What kind of reaction will I have to the vaccine?


      Severe side effects for the COVID-19 vaccine are extremely rare. When minor side effects occur, they are a normal sign your body is building protection to the virus, and most go away within a few days. These include soreness in the arm, fatigue, headache or a slight fever that lasts a day or two. If you have questions about whether the vaccine is safe for you, you should talk to your health care provider.

    • What is the risk of having an adverse reaction to the vaccine?

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      The risk of a medically significant adverse reaction to the COVID-19 vaccine is extremely low and the CDC and FDA are closely monitoring the safety of all approved vaccines. It’s important to distinguish between mild and expected reactions, like some soreness in the arm, fatigue, headache or a slight fever that lasts a day or two, and medically significant reactions, which are very rare. Cases of anaphylaxis (an allergic reaction) were occurring between 2 and 5 times for every 1 million COVID-19 vaccine doses. Cases of myocarditis have also been reported in some instances, particularly for teen and young adult men. Risks of contracting COVID-19 are still greater than myocarditis, experts now. 

      If you have a question about whether the vaccine is safe for you, talk to your health care provider.

    • How long after I get vaccinated will I experience side effects?


      Allergic reactions, which can be severe, typically happen within 15 minutes of vaccinations. Feelings of light-headedness and/or fainting, which are possible, also typically occur within 15 minutes of vaccination. For this reason, the CDC recommends that people be observed by health care personnel for 15 minutes after getting vaccinated. Side effects like sore arm, fatigue and headache are most common the day after vaccination, but most often occur 1 to 3 days after vaccination.

    • Can people who have had allergic reactions to vaccines in the past get the COVID-19 vaccine?


      The American College of Allergy, Asthma and Immunology recommends the following:

      • Anyone receiving the vaccine should be asked if he/she has a history of a severe allergic reaction to any prior vaccine. If the answer is yes, individuals should be referred to an allergist/immunologist for further evaluation prior to COVID-19 vaccination.
      • According to the CDC, if you have had a severe or an immediate allergic reaction of any severity within 4 hours after getting the first COVID-19 shot, you should not additional doses of that vaccine. Talk with your healthcare provider to see if additional doses of another type of vaccine may be given.
      • Additionally, patients who experience a severe or an immediate allergic reaction of any severity (hives, swelling, wheezing) or who have questions related to risk of an allergic reaction, may be referred to an allergist/immunologist to provide more care or advice.
      • People who have had allergic reactions should receive the COVID-19 vaccine in a health care setting where anaphylaxis can be treated and be observed for at least 15-30 minutes after injection to monitor for any adverse reaction.
      • The mRNA (Pfizer, Moderna) and adenovirus vector (Johnson & Johnson) COVID-19 vaccines should not be administered to individuals with a known history of a severe allergic reaction to any component of a particular vaccine.
    • I heard the vaccine can cause paralysis. Is that true?


      Severe side effects for the COVID-19 vaccine are extremely rare. 

      On July 12, the Food and Drug Administration announced it is adding a warning label to the Johnson & Johnson COVID-19 vaccine, noting increased risk of a rare neurological syndrome called Guillain-Barré syndrome, which can cause paralysis. The new warning label is based on preliminary data, after about 100 reports of Guillain-Barré syndrome were detected in the Vaccine Adverse Event Reporting System, out of more than 12.8 million doses of the Johnson & Johnson vaccine administered.

      The CDC continues to advise that everyone 5 years of age and older receive a COVID-19 vaccine. The risk of severe adverse events after any COVID-19 vaccination remains rare, far lower than adverse health outcomes associated with contracting COVID-19.

      The CDC and FDA will continue to provide monitoring and treatment information to health care providers and vaccine recipients. 

      If you have questions about whether the vaccine is safe for you, you should talk to your health care provider.

    • How much testing of the vaccine was there on people of color?

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      Everyone is susceptible to infection by the coronavirus. Therefore, it’s important to have diversity among participants in clinical trials that measure a potential vaccine’s safety and effectiveness. Safety and effectiveness for all groups of people is particularly important for a COVID-19 vaccine because of the virus’s disproportionate impact on people of color, people with underlying medical conditions and the elderly. A vaccine that is not sufficiently tested in a diverse clinical trial pool could lead to unexpected effects that didn’t appear in a trial with a more general population.

      Approximately 42% of participants in Pfizer BioNTech’s worldwide clinical trials, and 37% of the Moderna study population were from communities of color, which is similar to the diversity of the U.S. at large.

    • What is the difference between emergency use authorization and ‘normal’ authorization?


      Emergency use authorization is a process by which the FDA can authorize use of a medication or vaccine with less data if the benefit of the vaccine has been shown to outweigh the risk. EUAs can be issued only during a declared emergency, such as the COVID-19 pandemic. Vaccines issued an EUA will continue to be studied and have additional safety monitoring and informed consent and education associated with them.

    • How were the vaccines approved without meeting the minimum FDA testing period requirements?


      COVID-19 vaccines were developed quickly, but routine processes and procedures remained in place to ensure safety. The Pfizer vaccine was granted full FDA approval in August 2021 and the Moderna vaccine in February 2022. The Johnson & Johnson vaccine is still licensed under Emergency Use Authorizations, but is expected to apply for full approval. 

    • I’m suspicious of the technology used to make the vaccine. It’s like something from science fiction.

    • Are there any pre-existing conditions that would prevent someone from receiving the vaccine?


      • Children age 5 to 11 should receive a small dose of the Pfizer-BioNTech vaccine. Children and teens age 12-18 can receive the same dose of the Pfizer-BioNTech vaccine as adults. Those under age 19 are not eligible to receive the Moderna or Johnson & Johnson vaccines.
      • Anyone who has a fever or other symptoms may not be able to get the vaccine until their symptoms resolve. This includes those who have symptoms or are positive for COVID-19.
      • People with documented anaphylactic reactions to vaccines and individuals with a known allergy to any of the vaccine components should not be immunized.
    • Are there any conditions that would cause someone to delay receiving the COVID-19 vaccine?


      In some instances, a person may need to wait to be vaccinated for COVID-19. These include:

      • People who are moderately or acutely ill with something other than COVID-19. People who have mild respiratory symptoms (I.e. head cold, diarrhea) can still be vaccinated. People who are taking antibiotics but are not currently feeling ill can be vaccinated, too.
      • More specific circumstances should be discussed with your health care provider.
    • If someone has a severe reaction to COVID-19 vaccine, does it show that they had the virus in the past?

    • Are women more likely to experience side effects from the vaccine?


      An analysis from the first 13.7 million COVID-19 vaccine doses given to Americans found that side effects were more common in women. And while severe reactions to the COVID-19 vaccine are rare, nearly all the cases of anaphylaxis, or life-threatening allergic reactions, occurred in women.

      The finding that women are more likely to report and experience unpleasant side effects to the COVID-19 vaccine is consistent with other vaccines as well.

    • If I get a fever after getting vaccinated for COVID-19, should I stay home?

    • I have a rash where I got vaccinated. Should I be concerned?


      Some people have experienced a red, itchy, swollen or painful rash in the arm where they got the COVID-19 vaccine. These rashes can start a few days to more than a week after the first shot and are sometimes quite large. These rashes are also known as “COVID arm.” If you experience a rash after getting the first shot and you are getting a two-dose vaccine, you should still get the second shot at the recommended interval, but you may want to get the second shot in the opposite arm. If the rash is itchy, you can take an antihistamine. If it is painful, you can take a pain medication like acetaminophen or a non-steroidal anti-inflammatory drug.

    • I’ve heard that some people have swollen lymph nodes after vaccination. Should I be concerned about that?

      Source: and

      A small number of people have reported swollen lymph nodes about two to four days after receiving the COVID-19 vaccine. The swelling is almost always on the side of the body in which the person was vaccinated and goes away within a couple of weeks. The swelling may show up on imaging scans, including mammograms. Some experts suggest waiting a few weeks after COVID-19 vaccination to schedule imaging, including mammograms. Others recommend telling the provider about your recent COVID-19 vaccination and working with him/her to follow up as needed if swollen lymph nodes are detected.

    • Can I drink alcohol after getting the vaccine?

    • How long does someone shed the vaccine?

    • I haven’t had any side effects after the vaccine. Does that mean it's not working?


      Just as some people experience side effects from medications and some don’t, people have varied reactions to vaccines. While we tend to hear only about the unpleasant reactions after the vaccine, a lot of people experience only mild discomfort or no symptoms at all after getting the shot.

    • I heard a nurse say she would not get the vaccine. If health care workers are not getting, why should I?

      Source: and

      Some health care workers are skeptical about the vaccine. They have concerns about the technology and the speed at which it was developed—the same issues that many in the community wonder about. It’s important to note that all the COVID-19 vaccines being used have gone through rigorous studies to ensure they are as safe as possible. Systems that allow CDC to watch for safety issues are in place across the entire country.

    • Are there any side effects that are different between races?


      Clinical trial data for the vaccines did not find specific safety concerns by age, race, ethnicity, chronic health conditions or prior coronavirus infection.

    • There have been reports that the vaccine may be related to cases of Bells Palsey--are there any other long lasting side effects related to the vaccine?


      Severe side effects for the COVID-19 vaccine are extremely rare. When minor side effects occur, they are a normal sign your body is building protection to the virus, and most go away within a few days. There is no definitive link between the vaccine and paralysis, a symptom of Bell’s Palsey. If you have questions about whether the vaccine is safe for you, you should talk to your health care provider.

    • If I or someone in my family has a severe reaction to the COVID-19 vaccine, what should we do?

      Source: and

      If someone has a severe allergic reaction after getting vaccinated, their provider will send a report to the Vaccine Adverse Event Reporting System, the national system that collects reports from health care professionals, vaccine manufacturers and the public about adverse events that happen after vaccination. Reports of adverse events that are unexpected, appear to happen more often than expected or have unusual patterns are followed up with specific studies.

      Benefits for those who have serious physical injury as a direct result of the COVID-19 vaccine may be available through the federal Countermeasures Injury Compensation Program within one year. Individuals or their family members must make a claim within one year and provide proof that a qualified injury was directly caused by the vaccine.

    • How do we know the vaccine is safe long-term?



  • How are the vaccines being distributed?

  • Can any pharmacy, clinic or hospital offer the COVID-19 vaccine?


    To receive and administer the COVID-19 vaccine and supplies, providers must enroll in a federal vaccine distribution program, coordinated through the state immunization program (unless they are part of a national chain that registered directly with the CDC). The federal government will procure and distribute the vaccine at no cost to enrolled providers.

  • If I’ve already had COVID-19 and recovered, do I need vaccine?

    Source: and

    Yes. Due to the severe health risks associated with COVID-19 and the fact that reinfection with COVID-19 is possible, you should be vaccinated regardless of whether you already had COVID-19 infection.  If you were treated for COVID-19 symptoms with monoclonal antibodies or convalescent plasma, you should also wait 90 days before getting a COVID-19 vaccine. Talk to your health care provider if you are unsure what treatments you received or if you have more questions about getting a COVID-19 vaccine.

  • If I receive a first vaccine dose, how will I know when to get the second dose?

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    Two of the three available vaccines are based on a two-dose regimen and the great majority of public health officials and vaccination experts believe it is important to stay with that two-dose regimen because that’s what was shown to be effective during the clinical trials. Most providers will notify you when it’s time to schedule your second dose. If you don’t hear, check with the provider who gave you your first dose. 

  • Do I need a booster shot? 


    Everyone age 12 and older should get a COVID-19 booster dose. The CDC advises that people who are 12 or older who received the Moderna and Pfizer vaccine should get a booster at least six months after their second shot. Johnson & Johnson recipients who are 12 and older should get a booster at least two months after their initial shot.  At this time, a booster is not recommended for children and adolescents younger than 12. In March 2022, the FDA also recommended that people age 50 and over who are fully vaccinated and have received one booster dose should consider a second booster dose. Talk with a health care provider to see if you should get a second booster. 

    The CDC recommends that people who received the Johnson & Johnson vaccine get a Pfizer or Moderna booster. The CDC advises people who got a Pfizer or Moderna vaccine to get the same booster as their initial vaccine, but allows them to mix and match (i.e., get a different COVID-19 booster than their initial vaccine) depending on preference or availability—with the exception of adolescents age 16-17 who are only eligible to receive the Pfizer vaccine.

    The emergence of the Omicron variant underscored the importance of vaccination, boosters, and preventive efforts to protect against COVID-19. CDC recommendations on booster doses are based on the latest data, with the goal of ensuring that people have optimal protection against COVID-19 infection, severe illness and death.

    The vaccines work. The COVID-19 vaccines continue to be highly effective in reducing risk of severe disease, hospitalization, and death. CDC data show that in August 2021, the risk of dying from COVID-19 in the U.S. was more than 21 times greater for unvaccinated people than for fully vaccinated people. However, scientists are starting to see reduced protection against mild and moderate disease, especially among certain populations. CDC’s latest guidance is in response to this waning of the efficacy and the recent emergence of the Omicron variant.

  • Could you discuss the differences between the vaccines?

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    Three vaccines are currently licensed: One developed by Pfizer/BioNTech, one by Moderna and one by Johnson & Johnson. Having different types of vaccines available for use, especially ones with different storage and handling requirements and dosing recommendations, can offer more options and flexibility for jurisdictions and vaccine providers. 

    The Pfizer and Moderna vaccines are mRNA vaccines that have a piece of mRNA specific for the SARS-CoV-2 spike protein. They have similar efficacy and safety profiles.  

    The main differences between the Pfizer and Moderna vaccines include the ages of individuals eligible to get the vaccines, the length of time between doses, the requirements for storage and the preparation of the vaccine. The Pfizer and Moderna vaccines have also received full approval from the FDA.

    Johnson & Johnson is an adenovirus vector vaccine.  

    In clinical trials, people reported fewer and milder side effects from the Johnson & Johnson vaccine. 

    The Johnson & Johnson vaccine is easier to administer as well—it only requires one dose and can be stored in regular refrigerators. Unused doses have a longer shelf life as well. Use of the Johnson & Johnson vaccine was paused in April 2021 while federal health officials investigated a small number of blood clots reported after vaccination. A panel of experts decided that the benefits of the vaccine outweighed the risks and cleared it for use again.   

  • Is one manufacturer's vaccine better than another?


    The most crucial piece of data about a vaccine is its ability to prevent severe illness and death; and all vaccines approved for use in the U.S. meet similar standards for severe illness/death. Comparing how well vaccines prevent mild illness is more difficult, experts caution, because the vaccine trials were done during different timeframes and in different parts of the world, meaning that the amount of virus circulating and the variants were different. A final factor is distribution of the vaccine, some require only one dose and can be stored at regular temperatures, while other require multiple doses and extreme cold storage.

  • Who is at risk for the blood clotting disorder associated with the Johnson & Johnson vaccine?


    The likelihood of the blood clotting disorder resulting from the Johnson & Johnson vaccine is extremely rare. The risk varies by age and gender. There have been fewer than 1 case per million for men and for women who are 50 years or older; the risk is estimated to be about 7 cases per million for women age 18 to 49. If you have questions about the Johnson &Johnson vaccine or other vaccines, talk to your health care provider.

  • If a vaccine requires more than one dose or a booster, can they be from different manufacturers?


    Initial doses of the vaccine requiring two doses (Pfizer/BioNTech and Moderna) should be from the same manufacturer when possible. The CDC’s clinical guidance advises people to get the same booster as their initial vaccine, but allows people to mix and match (i.e. get a different COVID-19 booster than their initial vaccine) if they have a different preference.

  • How can I keep myself safe while getting vaccinated?


    When going to get vaccinated, be sure to take the following precautions:

    • If you think you have COVID-19, notify the health care provider before your visit and follow their instructions.
    • You and your health care provider will both need to wear a mask.
    • Do not touch your eyes, nose or mouth.
    • Stay at least 6 feet away from others while inside and in lines.
  • Can I get the COVID-19 vaccine if I’ve had another vaccine or am scheduled to get another vaccine soon?


How vaccine works

  • How will a COVID-19 vaccine work in my body?


    The COVID-19 vaccine teaches your immune system to recognize the coronavirus. When you get the vaccine, your immune system makes antibodies (“fighter cells”) that stay in your blood and protect you in case you are infected with the virus. You get protection against the disease without having to get sick.

    When enough people in the community can fight off the coronavirus, it has nowhere to go.

  • Are the current vaccines effective against variants?


    Yes. While COVID-19 vaccines are highly effective, no vaccine provides 100% immunity. Because this is a new virus, scientists and medical experts continue to monitor how long immunity lasts, whether some groups may need additional doses, and how well the vaccines protect against new variants of the virus. Vaccinated people experience breakthrough cases, but they are much more likely to have milder symptoms than unvaccinated people with COVID-19. Unvaccinated people continue to account for the vast majority of severe cases, hospitalizations, and deaths from COVID-19. 

  • How do they know the amount of dosage my body needs?

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    When authorizing vaccines, age is more important than weight. The PfizerBioNTech COVID-19 vaccine for children ages 5 through 11 contains a lower dose (10 micrograms) than the vaccine used for older children and adults (30 micrograms). This dose was shown in clinical trials to provide a sufficient immune response in school-aged kids Smaller needles are being used to deliver the vaccine to children ages 5 through 11.

    Immune cells, called T cells and B cells, must be able to recognize the component of the vaccine, so that if a person comes into contact with that virus or bacteria again, these educated cells can become active and protect the person from an infection. Since these cells are present throughout the body, they are usually educated near where the vaccine is given and then the cells, not the vaccines, travel throughout the body.

  • Do you have to have U.S. citizenship or permanent residency to receive the vaccine?

  • Do I need to get tested for COVID-19 before receiving either dose of vaccine?


    No, you do not need to get tested for COVID-19 prior to receiving a COVID-19 vaccine. If you are exhibiting symptoms of COVID-19 or have known current COVID-19 infection, you should not get vaccine until after you have completed your isolation requirements. This recommendation applies to persons who develop COVID-19 infection before receiving any vaccine doses as well as those who develop COVID-19 infection after the first dose but before the second dose.

  • Can I take my routine medications (I.e. blood pressure, cholesterol) the day I’m scheduled to get my COVID-19 vaccination?

  • Who can’t get the vaccine?

    Source: and

    • Children age 5 to 11 are eligible to receive a small dose of the PfizerBioNTech vaccine. Children age 12-18 are eligible to receive the Pfizer-BioNTech vaccine with a standard dose. Those under age 19 are not eligible to receive the Moderna or Johnson & Johnson vaccine.
    • As with other vaccines, anyone who has a fever or other symptoms may not be able to get the vaccine until their symptoms resolve. This includes those who have symptoms or are positive for COVID-19.
    • There is also caution for people with documented anaphylactic reactions to vaccines. Individuals with a known allergy to any of the vaccine components should not be immunized.
  • If I live with someone who has a health concern (I.e. pregnant woman, someone with cancer), can I still get vaccinated?



  • Who is paying for the COVID-19 vaccines?


    Vaccine doses purchased with U.S. taxpayer dollars will be given to the American people at no cost. However, vaccination providers can charge an administration fee for giving someone the shot. Vaccination providers can be reimbursed for this by the patient’s public or private insurance company or, for uninsured patients, by the Health Resources and Services Administration’s Provider Relief Fund. No one can be denied a vaccine if they are unable to pay the vaccine administration fee.

  • What is a vaccine administration fee?


    The vaccine administration fee is the fee a health care provider charges to give you the vaccine. This is separate from the cost of the vaccine itself, which the federal government will cover.


Pregnancy, Breastfeeding and Fertility



  • Is it safe for kids and teens to get the COVID vaccines?


    Yes. Keeping children safe and healthy is top of mind for parents, and scientists have worked to ensure the vaccine is safe for children ages 5-17. Before being authorized for children, scientists and medical experts completed their review of safety and effectiveness data from clinical trials of thousands of children. The Pfizer COVID-19 vaccine was rigorously tested and reviewed, and more than 11 million adolescents ages 12-17 have already received the COVID-19 vaccine.  In November 2021, the Pfizer vaccine is also authorized for children ages 5-11. Data from trials will continue to be collected for two years after each vaccine is first administered to ensure that they are safe for the long term. As with all vaccines, there will be ongoing monitoring among people who are vaccinated.

  • What if my child has asthma?

  • Can children under 5 get the vaccine safely?

  • Children are much less likely than adults to have severe disease from COVID-19, so why do they need to be vaccinated?


    COVID-19 can cause significant illness in children. In children for whom COVID-19 caused serious illness, half had an underlying condition, and half did not. This is similar to influenza. We need to vaccinate children because we do not know which children may be at higher risk of serious, possibly life-threatening illness. Children can also transmit the virus, including to more vulnerable adults who are in their family or in their school, so it is important that children be included in the vaccine distribution in order to reduce community spread.


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