COVID-19 vaccine frequently asked questions

Below are commonly asked questions and answers regarding COVID-19 vaccination. This page has useful information before you are able to get vaccinated, during your vaccine appointment, and after you receive the vaccine, as well as information about vaccine safety.

Table of Contents

Before getting vaccinated

Will I have to pay for the vaccine?

No. The vaccine is being provided free of charge to all individuals by the federal government.  If you have insurance, it will be billed at no cost to you. However, you do not need to be insured to receive the vaccine. You will never be asked for a credit card number to make an appointment.  

May undocumented immigrants receive the vaccine for free?

Yes.  The vaccine itself is free for all individuals in Massachusetts.  Health insurance (including Medicare and Medicaid) will cover the cost of administering the vaccine.  For patients without health insurance, health care providers may request reimbursement from the federal government for the cost of administering vaccine to undocumented immigrants.

Can I still get the vaccine if I don't have an ID card?

Yes. You can get a vaccine even if you do not have insurance, a driver’s license or a Social Security number. For more information, visit How to prepare for your COVID-19 vaccine appointment.

Will getting the vaccine negatively impact a person’s immigration status?

No.  The federal government has confirmed that it will not consider COVID-19 treatment (including a vaccine) as part of a determination of whether someone is a “public charge” or as it relates to the public benefit condition for certain individuals seeking an extension of stay or change of status, even if the vaccine is paid for by Medicaid or other federal funds.

Is a patient’s vaccination record protected from disclosure?

The Department of Public Health will maintain an electronic record of each patient in Massachusetts who receives the COVID-19 vaccine.  The vaccine database is kept confidential like a patient’s medical record with his or her doctor.

Will I need to be tested for COVID-19 before getting the vaccine?

No, a COVID-19 test is not needed before getting the vaccine. 

If I’m unvaccinated but have already had COVID, should I still get vaccinated?

Yes. You should get a COVID-19 vaccine even if you already had COVID-19. No currently available test can reliably determine if you are protected after being infected with the virus that causes COVID-19. However, you may consider delaying your next vaccine dose (primary dose or booster) by 3 months from when your symptoms started or, if you had no symptoms, when you first received a positive test.

Getting a COVID-19 vaccine after having COVID-19 provides added protection to your immune system. People who already had COVID-19 and do not get vaccinated after their recovery are more likely to get COVID-19 again than those who get vaccinated after their recovery.

After having COVID, how long do I need to wait to get vaccinated?

You should wait until 10 days after symptoms started or, if you didn’t have symptoms, 10 days after your test was positive.  This to ensure that you don’t spread COVID-19 to others.

If you recently had COVID-19, you may consider delaying your next COVID-19 vaccine (either primary dose or booster) by 3 months from when your symptoms started or when you received a positive test.

Should I still get vaccinated if I received a monoclonal antibody treatment for COVID? How long do I need to wait to get vaccinated after treatment?

Yes. Per CDC, individuals who received monoclonal antibodies for treatment of COVID-19 should be vaccinated and do not need to wait to receive a COVID-19 vaccine.

Can people who live in another state or country part time (e.g., students, retirees, people with dual citizenship) get the COVID-19 vaccine in Massachusetts?

Yes. The Massachusetts COVID-19 Vaccination program is intended for individuals who live, work or study in the Commonwealth.  You may also get your second dose in Massachusetts if you received the first dose in another state. Please be sure to keep the vaccination card you were given at the time of the first dose. 

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

COVID-19 vaccines available in the United States are effective at protecting people—especially those who are boosted— from getting seriously ill, being hospitalized, and even dying. As with other diseases, you are protected best from COVID-19 when you stay up to date with the recommended vaccines.

The combination of getting vaccinated and following CDC’s recommendations to protect yourself and others will offer the best protection from COVID-19.

Will vaccines work against COVID-19 variants?   

Viruses constantly change through mutation and sometimes these mutations result in a new variant of the virus. Some variants emerge and disappear while others persist. New variants will continue to emerge. CDC and other public health organizations monitor all variants of the virus that causes COVID-19 in the United States and globally. 

What is the difference between emergency use authorization and full approval?

Before vaccines are made available to people in real-world settings, FDA assesses the findings from clinical trials. The four COVID-19 vaccines available in the US met FDA’s safety and effectiveness standards and been granted Emergency Use Authorizations (EUAs). The EUAs allowed the vaccines to be quickly distributed for use while maintaining the same high safety standards required for all vaccines. Learn more in this video about EUAs.

FDA has now also granted full approval for Pfizer-BioNTech (COMIRNATY) COVID-19 Vaccine for people ages 12 years and older and for Moderna (Spikevax) COVID-19 Vaccine for people ages 18 years and older. Before granting approval, FDA reviewed evidence that built on the data and information submitted to support the EUA. This included preclinical and clinical trial data and information, as well as details of the manufacturing process, vaccine testing results to ensure vaccine quality, and inspections of the sites where the vaccine is made. These vaccines were found to meet the high standards for safety, effectiveness, and manufacturing quality FDA requires of an approved product. Learn more about the process for FDA approval.

I was vaccinated for COVID-19 outside of the United States. Do I need to be revaccinated in the U.S. with another primary series? Can I complete my series here in the US? Am I eligible for a booster?

It depends on your health status, which vaccine you received, and whether you received a full primary series.

For the best protection, CDC recommends everyone stay up to date with COVID-19 vaccines, including people who received a COVID-19 vaccine outside of the United States. A person is up to date with their COVID-19 vaccination when they have received all doses in the primary series and all recommended boosters, when eligible.

Specific recommendations for people vaccinated outside of the United States (shown below) depend on whether:

  • The vaccine(s) received are accepted in the United States
  • The primary series was completed
  • A booster dose was received

For more information go to COVID-19 Vaccines for People Vaccinated Outside the United States | CDC

I was vaccinated outside of the United States with a COVID-19 vaccine not authorized in the U.S.  I am immunocompromised. Can I get a 3rd dose of a primary series, for immunocompromised people, in the U.S.?

Yes. Moderately or severely immunocompromised people ages 12 years and older should get an additional primary dose of Pfizer COVID-19 vaccine at least 28 days after receiving the second vaccine dose of their primary series.

During your appointment

What can I expect at my appointment to get vaccinated for COVID-19?

Please visit Getting Your COVID-19 Vaccine | CDC for tips on what to expect when you get vaccinated, what information your provider will give you, and resources you can use to monitor your health after you are vaccinated.

Do I need to wear a mask when I receive a COVID-19 vaccine? 

Yes, you must wear a mask that covers your nose and mouth during your appointment.

How long do I have to wait between the first and second dose of the COVID-19 vaccine for Pfizer, Moderna or Novavax?

Your second shot is recommended at 21 days for Pfizer and Novavax and 28 days for Moderna. However, if you get the second shot at any time after the recommended date, you are still considered fully vaccinated. You should not get the second dose earlier than 21 days for Pfizer and Novavax or 28 days for Moderna. The Janssen (Johnson & Johnson) vaccine is only one dose. 

Some people who are not yet vaccinated — ages 12 through 64 years who are not moderately or severely immunocompromised, particularly males ages 12 through 39 years — may benefit from getting their second mRNA COVID-19 vaccine dose 8 weeks after their first dose, instead of the timeline noted above. Ask your healthcare provider for more information. 

How effective is one dose of a Pfizer, Moderna or Novavax COVID-19 vaccine compared to two doses?

The Pfizer, Moderna and Novavax COVID-19 vaccines were not studied for use as a single dose. People should get both doses of the vaccine to be fully vaccinated.

Will I be monitored after being vaccinated?

People who have a history of anaphylaxis (severe allergic reaction) from any cause ​are observed for 30 minutes. All others are monitored for 15 minutes.

Will I receive anything to show proof of vaccination?

You should receive a vaccination card or printout that tells you what COVID-19 vaccine you received, the date you received it, and where you received it. Please be sure to keep this card for your second dose. You may take a photo of your card as a backup digital copy.

You should receive a paper or electronic version of a fact sheet that tells you more about the specific COVID-19 vaccine you are being offered. Each COVID-19 vaccine has its own fact sheet that contains information to help you understand the risks and benefits of receiving that specific vaccine: Comirnaty/Pfizer, Moderna, Novavax and Johnson & Johnson (Janssen).

What should I do if I lose my COVID-19 Vaccination Record Card?

You have a few options:

  1. Contact your healthcare provider or the location where you were vaccinated. They can print out another copy of your record.
  2. Get a digital copy of your vaccination record through MyVaxRecords.Mass.Gov.
  3. Your record will also be in v-safe, if you enrolled in the program.  
  4. You can fill out an Immunization Record Request Form that goes directly to the state Department of Public Health. If you use this form, you will get a complete history of all vaccines you’ve gotten, not just the COVID-19 vaccine, and it can take up to 6 weeks to get your records.
    1. Please note that this form must be notarized before it is submitted and mailed in hard copy. You will receive a paper record of any immunizations you have received that were reported to the MIIS. You will not receive a COVID-19 vaccine card.

If you were vaccinated at a mass vaccination site, view the instructions for vaccination record requests.

After getting vaccinated

What should I do if I experience symptoms after receiving a COVID-19 vaccine?

Some people have side effects after being vaccinated (such as tiredness, headache, and pain at the injection site), which are normal signs that your body is building protection. These side effects may affect your ability to do daily activities, but they should go away in a few days. If you develop respiratory symptoms like runny nose, cough, or loss of sense of smell or taste, you should consider getting tested for COVID-19 or talk to your healthcare provider. It is possible to get COVID-19 even after you get the vaccine. Stay home if you are sick and avoid close contact with others.  You may wish to check with your employer about how this will impact your work.

If you have any significant pain or discomfort, talk to your healthcare provider, who may recommend over-the-counter medicine, such as ibuprofen or acetaminophen. To reduce pain and discomfort where you got the shot apply a clean, cool, wet washcloth over the area, and use or exercise your arm.  To reduce discomfort from fever, drink plenty of fluids and dress lightly. In most cases, discomfort from fever or pain is normal, but contact your healthcare provider if:

  • the redness or tenderness where you got the shot increases after 24 hours
  • your side effects are worrying you or do not seem to be going away after a few days

How do I report if I have any side effects after getting the COVID-19 vaccine?

V-safe is a smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after you receive a COVID-19 vaccination. Through v-safe, you can quickly tell CDC if you have any side effects after getting the COVID-19 vaccine. Depending on your answers, someone from CDC may call to check on you and get more information. And v-safe will remind you to get your second COVID-19 vaccine dose if you need one. To sign up for v-safe, please visit V-safe After Vaccination Health Checker | CDC.

If you have any concerns, you can also call your healthcare provider.  You or your provider can report any side effects to the Vaccine Adverse Event Reporting System (VAERS), which is a national system run by the federal government.

How long after getting the COVID-19 vaccine does it take to be effective?

It usually takes a few weeks for the body to build immunity after vaccination. That means it's possible a person could be infected with the virus that causes COVID-19 just before or just after vaccination and get sick. This is because the vaccine has not had enough time to provide protection. You are considered fully vaccinated if you have received two doses of either the Moderna, Pfizer or Novavax COVID-19 vaccines or a single dose of the Janssen (Johnson & Johnson) vaccine more than 14 days ago. 

How long does protection from the COVID-19 vaccines last?

It’s not yet known how long COVID-19 vaccine protection lasts. Recent studies show that protection against the virus may decrease over time. That is why the CDC recommends certain groups get a booster shot.

When can I get a booster shot?

For information about what boosters are, who is eligible, and how to get one, visit COVID-19 booster frequently asked questions | or COVID-19 Vaccine Boosters | CDC

There is a tool to help you determine when or if you (or your child) can get one or more COVID-19 boosters. It is labelled ‘Find Out When You Can Get Your Booster’ and can be found at COVID-19 Vaccine Boosters | CDC.

Can I get a second booster shot?

For information about what boosters are, who is eligible, and how to get one, visit COVID-19 booster frequently asked questions | or COVID-19 Vaccine Boosters | CDC

There is a tool to help you determine when or if you (or your child) can get one or more COVID-19 boosters. It is labelled ‘Find Out When You Can Get Your Booster’ and can be found at COVID-19 Vaccine Boosters | CDC

Who is eligible to get an additional primary series dose?

For information about vaccine doses, who is eligible, and how to get one, visit Massachusetts COVID-19 Vaccine Information | or Stay Up to Date with Your COVID-19 Vaccines | CDC or ask your healthcare provider for more information. 

Vaccine safety

Is the Johnson & Johnson vaccine safe?

All vaccines in the United States must go through three phases of clinical trials to ensure they are safe and effective. All COVID-19 vaccines used in the US are safe and provide high levels of protection against serious illness, hospitalization, and death.

In most situations, Pfizer-BioNTech, Moderna or Novavax COVID-19 vaccines are preferred over the J&J/Janssen COVID-19 vaccine for primary and booster vaccination due to the risk of serious adverse events. The J&J/Janssen COVID-19 vaccine may be considered in some situations, including for persons who:

  • Had a severe reaction after an mRNA vaccine dose or who have a severe allergy to an ingredient of Pfizer-BioNTech or Moderna (mRNA COVID-19 vaccines).
  • Would otherwise remain unvaccinated for COVID-19 due to limited access to Pfizer-BioNTech or Moderna (mRNA COVID-19 vaccines).
  • Wants to get the J&J/Janssen COVID-19 vaccine despite the safety concerns.

For more information go to Johnson & Johnson’s Janssen COVID-19 Vaccine Overview and Safety | CDC

How do we know if the vaccine is safe?

It’s important to know that vaccines go through more testing than any other pharmaceuticals.  First, small groups of people receive the trial vaccine. Next, vaccine is given to people with certain characteristics (e.g., age, race, and physical health). Then, vaccine is given to tens of thousands of people and tested for effectiveness and safety.

After that, the CDC’s Advisory Committee on Immunization Practices (ACIP) looks at the data to see whether the vaccine works and is safe.  They give advice to the United States Food and Drug Administration (FDA). The FDA looks at the data and the advice from the ACIP and decides whether to approve the vaccine. The vaccine is only approved after all of these steps are done, and the experts are sure that it works and is safe.

Visit Ensuring the Safety of COVID-19 Vaccines in the United States | CDC for more information.

How is it safe if it happened so fast?

The timeline to develop a COVID-19 vaccine was sped up but never cut corners on safety. Here is how:

  1. We already had helpful information: The COVID-19 virus is a part of a coronavirus family that has been studied for a long time. Experts learned important information from other coronavirus outbreaks that helped them to develop the COVID-19 vaccine, so we weren’t starting from scratch.
  2. Governments funded vaccine research: The United States and other governments invested a lot of money to support vaccine companies with their work. Working together with other countries also helped researchers move quickly.
  3. A lot of people participated in clinical trials: Many people wanted to help by being in the vaccine studies. Companies didn’t need to spend time finding volunteers.
  4. Manufacturing happened at the same time as safety studies: Vaccine companies were able to make and store doses of vaccine at the same time as studies (called clinical trials) were happening to show that the vaccines were safe and effective. This meant vaccines were ready to be distributed once they were approved.

How is it safe if we don’t know the long-term side effects?

The Pfizer and Moderna COVID-19 vaccines are what experts call messenger RNA vaccines, or mRNA vaccines for short. The Janssen (Johnson & Johnson) vaccine is called a viral vector vaccine. Both types of vaccines have been studied in animal and human trials for years. On the other hand, COVID-19 has only been around for about a year and the long-term side effects of COVID-19 infection are mostly unknown and may be serious. Therefore, getting vaccinated is the best choice for long-term health and safety.  

Novavax is the first COVID-19 protein subunit vaccine that the CDC has recommended for use in the United States. Protein subunit vaccines contain harmless pieces (proteins) of the COVID-19 virus alongside another ingredient called an adjuvant that helps the immune system respond to the virus in the future if exposed. Vaccines using protein subunits have been used for more than 30 years in the United States, beginning with the first licensed hepatitis B vaccine. Other protein subunit vaccines used in the United States today include those to protect against influenza and acellular pertussis (whooping cough). 

Experts will continue to track COVID-19 vaccine side effects. People in clinical trials will be tracked for 2 years. Other people who get the vaccine can use a tool called v-safe on their smartphones to quickly tell the CDC if you have any side effects after getting the COVID-19 vaccine. V-safe users can share information for up to one year after their vaccine. Learn more at V-safe After Vaccination Health Checker.

Do the COVID-19 vaccines have any side effects?

Some people may have side effects after being vaccinated, which are normal signs that your body is building protection. These side effects may affect your ability to do daily activities, but they should go away in a few days. The most common side effects are minor and include tiredness, headache, pain at the injection site, muscle and/or joint pain, chills, nausea and/or vomiting, and fever. For more information see Possible Side Effects After Getting a COVID-19 Vaccine | CDC

Can a COVID-19 vaccine make me sick with COVID-19?

No. The Pfizer, Moderna, Novavax and Janssen (Johnson & Johnson) vaccines do not contain the live virus that causes COVID-19. This means that a COVID-19 vaccine cannot make you sick with COVID-19. (source: Facts about COVID-19 Vaccines ( Therefore, if you test positive for COVID-19, even if you have gotten the vaccine, you would need to isolate.

Should someone with a history of allergies get the COVID-19 vaccine?

You should not get the Pfizer, Moderna, Novavax or Janssen (Johnson & Johnson) COVID-19 vaccines if you have a history of severe allergic reaction (also called anaphylaxis) to any ingredient in the vaccine. If you have a history of a severe allergic reaction  to something else that’s not in the vaccine, discuss with your health care provider before receiving the vaccine.

Although there is a small chance that the COVID-19 vaccines could cause a severe allergic reaction, this would usually happen within a few minutes to one hour after getting the vaccine. Everyone, even if they don’t have allergies, is monitored for at least 15 minutes after getting a COVID-19 vaccine.

What are the ingredients in the vaccine?

COVID-19 vaccine ingredients are considered safe for most people. Nearly all of the ingredients in COVID-19 vaccines are ingredients found in many foods—fats, sugar, and salts. Exact vaccine ingredients vary by manufacturer. Pfizer and Moderna COVID-19 vaccines also contain messenger RNA (mRNA). Novavax COVID-19 vaccines also contains harmless pieces (proteins) of the virus that causes COVID-19, and the Johnson & Johnson/Janssen COVID-19 vaccine contains a harmless version of a virus unrelated to the virus that causes COVID-19. These all give instructions to cells in your body to create an immune response. This response helps protect you from getting sick with COVID-19 in the future. After the body produces an immune response, it discards all the vaccine ingredients just as it would discard any information that cells no longer need. This process is a part of normal body functioning. 

COVID-19 vaccines do NOT contain ingredients like preservatives, tissues (like aborted fetal cells), antibiotics, food proteins, medicines, latex, or metals. 

Learn more about what ingredients are and are not in Pfizer-BioNTech, Moderna, Novavax or Johnson & Johnson/Janssen COVID-19 vaccines. 

I would like to have a baby one day. Is it safe for me to get a COVID-19 vaccine?

Yes. The CDC recommends COVID-19 vaccination for people trying to get pregnant now, or who might become pregnant in the future. There is no evidence that antibodies made following COVID-19 vaccination or that vaccine ingredients will cause any problems with becoming pregnant now or in the future. In fact, there is no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems in women or men. Learn more at COVID-19 Vaccines for People Who Would Like to Have a Baby | CDC.

Can someone who is pregnant or breastfeeding get a COVID-19 vaccine?

Yes. The CDC and American College of Obstetricians and Gynecologists recommend COVID-19 vaccination for people who are pregnant or breastfeeding. COVID-19 infection during pregnancy increases the risk of severe illness and preterm birth.  Evidence about the safety and effectiveness of COVID-19 vaccination during pregnancy has been growing. Data suggest that the benefits of receiving a COVID-19 vaccine outweigh any known or possible risks of vaccination during pregnancy.

Getting vaccinated is a personal choice for people who are pregnant or breastfeeding. If you have questions, discuss vaccination with your healthcare provider.

Are the COVID-19 vaccines safe for children?

Yes. The CDC recommends everyone ages 6 months and older get a COVID-19 vaccine. Scientists have conducted clinical trials with thousands of children and determined it to be safe and effective. Learn more:

Will a COVID-19 vaccine change my DNA?  

No. The COVID-19 vaccines do not change or interact with your DNA in any way.

Vaccines teach our immune system how to fight against a specific virus. They work with the body’s natural defenses to safely develop immunity to disease.  In order to do its job, the COVID-19 vaccine doesn’t need to go inside the nucleus of the cell, which is where our DNA is kept. This means the vaccine never interacts with our DNA in any way and has no way to change it.

At the end of the process, our bodies have learned how to protect against future infection. That immune response and making antibodies is what protects us from getting infected if the real virus enters our bodies. (source: Facts about COVID-19 Vaccines (

More information

Visit these frequently updated Centers for Disease Control and Prevention (CDC) web pages on COVID-19 vaccination:

Download this FAQ in multiple languages

Help Us Improve with your feedback