Sign In
Boston Public Health Commission Home

Vaccine FAQs

Updated January 26, 2021: Information is still evolving rapidly and BPHC will update this information as new and relevant information becomes available and identify new and updated questions in red.

Click on a question to jump to the answer.





1. How many vaccines and what types are in development?
Dozens of vaccines are now in development, and several are moving toward final development. Vaccines from two vaccine makers, Pfizer and Moderna, were approved in December 2020.

2. How many vaccines will be available in Massachusetts?
Vaccine distribution is being directed by the State. For up-to-date and accurate information, review the State's weekly COVID-19 vaccination report


3. Who will get the vaccine first?
The federal government has recommended, and the Massachusetts COVID-19 Advisory Group has agreed, that first doses of the vaccine will go to people at highest risk for contracting COVID-19, including healthcare workers, first responders (i.e. EMS, fire and police), and residents and staff of congregate care settings, including nursing homes, shelters and correctional institutions.

Massachusetts places equity as a core principle of its recommendations, going further than national recommendations by prioritizing all COVID-facing health workers, including food service and facility workers, as well as home health workers, including personal care attendants. Individuals in congregate settings, including shelters and correctional institutions are also prioritized.

The Commonwealth of Massachusetts developed the Massachusetts COVID-19 vaccine distribution and schedule that prioritizes our residents most at risk of contracting the virus and those most at risk of poor health outcomes if they contract the virus. The Massachusetts Department of Public Health is also overseeing the distribution. 

To find out when you can get vaccinated, click here.


4. Will residents be required to get the vaccine?
We don't know of any current plans to make COVID-19 vaccines mandatory, and the Biden administration has said that it does not plan to make the vaccine mandatory throughout the U.S.

5. Once the COVID-19 vaccine is available, where can I go to get it?
The Boston Public Health Commission is actively planning vaccine clinics for Boston residents. 

When the COVID-19 vaccine is available to the general public, the Boston Public Health Commission will work with the City of Boston, health centers and hospitals, the State, community organizations and others to ensure that the vaccine is accessible and that people know where to get it. We have utilized similar strategies to ensure flu vaccines and COVID-19 testing are available and accessible to all. 

Check back for updates on where you can get vaccinated when it is available.


6. Will I have to pay for the vaccine?
No. The vaccine is being provided free of charge by the federal government to all individuals, including those with no insurance, undocumented immigrants and international students.

Insurance companies are committed to not charging any out-of-pocket fees or co-payments related to COVID-19 vaccine administration. Additionally, all healthcare provider sites that receive COVID-19 vaccine must agree to not charge patients any out-of-pocket fees or deny anyone vaccination services.

Providers can be reimbursed from the federal level for some administration costs. However, patients or insurance will not be charged. It is part of the provider vaccination agreement that each provider must sign in order to receive any vaccine for distribution.



7. How do COVID-19 vaccines work?

The first available COVID-19 vaccines work by triggering the immune system to produce antibodies. These antibodies protect us from getting infected if the real virus enters our bodies. Antibodies are our bodies’ natural defense against diseases.

8. Does the vaccine keep me from getting COVID-19?
To be approved, a vaccine must be effective. The FDA requires that any vaccine be greater than 50% effective at preventing COVID-19.  Clinical trial data has shown the COVID-19 vaccines currently approved are very effective (up to 95 percent) in preventing COVID-19, particularly preventing the most severe cases of this virus.

The vaccine will be most effective in protecting you if you receive both doses in the series. If you only receive the first dose, you won't be as well-protected from COVID-19 as you could be.

In addition to receiving the vaccine, it is also important to keep wearing a mask and social distancing because:

  1. Not everyone will get the vaccine at once.

  2. Although it is not likely, it is still possible to get COVID-19 after getting the vaccine, as no vaccine is 100 percent effective.

  3. We're currently not sure yet how long the vaccine will protect you from COVID-19. Wearing a mask and practicing social distancing provides additional protection. [Top]

9. How many doses will I need?
Both the Pfizer and Moderna vaccines, and all but one of the COVID-19 vaccines that are currently in Phase 3 clinical trials in the United States, require two doses. The first dose starts building protection and the second dose, given a few weeks later, is needed to get the most protection the vaccine has to offer. For the Pfizer vaccine, the second dose will be three weeks after the first. For the Moderna vaccine, it will be four weeks later.

It is important that you get both doses. If you don't, you won't be as well-protected from COVID-19 as you could be.

Protection from the vaccine is not immediate. It will take 1 to 2 weeks following the second dose to be considered fully vaccinated and receive the highest level of protection (about 95%).

10. Do I have to keep wearing a mask if I get vaccinated?
The current answer is yes. Masks, physical distancing, testing, contact tracing, and vaccinations must all be combined to eliminate COVID-19. No strategy is 100% effective, including the vaccine. Until the number of cases of COVID-19 in our community is low enough to prevent spread, all prevention strategies will need to be used.

There is still much to be learned about how much vaccination may reduce the disease, severity, or transmission and how long protection lasts. So vaccinated persons should continue to follow all current guidance to protect themselves and others, including:

  1. Wearing a mask
  2. Staying at least 6 feet away from others
  3. Avoiding crowds
  4. Washing hands often with water and soap or use alcohol-based hand sanitizer
  5. Following Center for Disease Control and Prevention (CDC) travel guidance
  6. Following CDC's quarantine guidance after an exposure to someone with COVID-19
  7. Following any applicable workplace or school guidance [Top]

11. If I had COVID-19 already, do I need to get vaccinated?
COVID-19 vaccination should be offered regardless of history of prior symptomatic or asymptomatic COVID-19 infection. However, vaccination should be deferred until recovery from acute illness (if the person had symptoms) and criteria have been met to discontinue isolation.

There is no minimal interval between infection and vaccination. However, current evidence suggests reinfection is uncommon in the 90 days after initial infection and thus those with documented acute infection in the preceding 90 days may defer vaccination until the end of this period, if desired.

Healthcare providers have said they are still providing the vaccine to their staff who have had COVID previously.


12. How do we know if the vaccine is safe?

A vaccine must be safe and effective for the Federal Drug Administration (FDA) to approve it.  Vaccines go through more testing than any other pharmaceuticals or medicines. Before any vaccine is made approved and made available, it must go through rigorous development and testing. Manufacturing is critical — every dose must consistently be of high quality.

Additionally, extensive testing in clinical trials is conducted to prove safety. First, small groups of people receive the trial vaccine. Next, the vaccine is given to people with particular characteristics (e.g., age and physical health). Then, the vaccine is given to tens of thousands of people and tested for effectiveness and safety.

Of the more than 70,000 people who participated in the COVID-19 vaccine clinical trials, 10 percent were Black and 13 percent were Hispanic/Latinx participants. There were no serious safety concerns noted in the studies of these vaccines.

After that, the data is reviewed by the Food and Drug Administration (FDA), which along with an independent board, CDC's Advisory Committee on Immunization Practices (ACIP) approves the vaccine, makes its recommendations for use. These bodies are the final safeguards for the public – ensuring that any vaccine is both safe and effective.


13. Can I get COVID-19 from the vaccine or spread COVID-19 from the vaccine?
No, you cannot get COVID-19 from the vaccine or spread COVID-19 from the vaccine. The vaccine doesn't actually contain the virus that causes COVID-19, which means the vaccine itself won't cause you to get or spread COVID-19.

14. What are potential side effects of the vaccine?
Some people in the clinical trials reported mild side effects, which are signs the immune system is working. Soreness and/or redness at the injection site is the most common reaction. Reported side effects also include:

  • Headaches
  • Fatigue
  • Fever
  • Chills
  • Muscle pain
  • Pain in joints

For some people, these side effects were worse after the second dose.

Side effects from a vaccine usually go away on their own within a few days. You can take an over-the counter medicine, such as acetaminophen or ibuprofen to manage side effects after the vaccine. However, it is recommended that you avoid taking these medications right before getting your vaccine.

After receiving the vaccine, you will be instructed on how to manage these symptoms.

Everyone who gets the vaccine will be watched for 15 minutes after the injection to make sure they do not have any signs of an immediate adverse or allergic reaction. People who have severe allergies to other vaccines or injectable medications are watched for 30 minutes.

There have been no serious safety concerns, including deaths, noted in the studies of these vaccines.

15. Should I get the vaccine if I have allergies?
There are many types of allergies and many people with allergies should get vaccinated. Per CDC, there have been reports that some people have experienced severe allergic respiratory reactions - also known as anaphylaxis - after getting a COVID-19 vaccine. As an example, an allergic reaction is considered severe when a person needs to be treated with epinephrine or EpiPen© or if they must go to the hospital.

If you have had an immediate allergic reaction - even if it was not severe - to a vaccine or injectable therapy for another disease, ask your healthcare provider if you should get a COVID-19 vaccine. Your healthcare provider will help you decide if it is safe for you to get vaccinated. If you have allergies not related to vaccines, CDC recommends that people with a history of severe allergic reactions not related to vaccines or injectable medications - such as food, pet, venom, environmental, or latex allergies - get vaccinated. People with a history of allergies to oral medications or a family history of severe allergic reactions may also get vaccinated. For more information, click here.

Everyone who gets the vaccine will be watched for 15 minutes after the injection to make sure they do not have any signs of an allergic reaction. People who have severe allergies to other vaccines or injectable medications will be watched for 30 minutes.

The vaccine does not contain any food products, including eggs and does not include metals. Once you are able to get the vaccine, talk to your allergist if you have concerns.

16. Can children and infants get the COVID vaccine?
The Pfizer vaccine is approved for ages 16 years and older and the Moderna vaccine is approved for ages 18 years and older.

Some of the manufacturers have begun clinical trials on kids ages 12 and older, but no vaccine for children under the age of 16 has been approved yet. It will still be a couple of months to get through those trials and then get approval to administer to children.

We haven't seen anything on clinical trials for children 12 years and younger.

17. Can pregnant women and women who are breastfeeding take the COVID-19 vaccine? Studies are ongoing regarding the safety of COVID-19 vaccines in pregnant women and there is not data yet.
We do know that the COVID-19 vaccine is not a "live" vaccine. It does not enter the cells of the developing baby. In addition, we know that pregnant women who develop COVID-19 have an increased risk of severe illness and may have an increased risk of poor pregnancy outcomes like pre- term labor.

Pregnant women should discuss the risks and benefits of her healthcare provider to help them make an informed decision.

18. Given the differences between the different types/brands of vaccines, will it be communicated which vaccine patients are getting?
Yes, you will know which vaccine you are receiving. The Massachusetts Department of Public Health (MDPH) and the CDC have emphasized that primary care physicians should have that conversation with their patients that are concerned about any of the vaccines.

Due to vaccine availability, patients will not be able to choose which vaccines they receive. The two available vaccines are similar, in that they both require two doses and are both over 90% effective.

An individual must receive the same vaccine for both doses. There is not enough information to note if full efficacy is achieved with 2 doses of different vaccines.

19. Have there been complications found or warnings issued for those who've already taken the flu vaccine?
We are not aware that any warnings have been issued. But we are monitoring closely and will communicate further information that becomes available as necessary.

20. What do we really know about potential long-term effects?
Long-term effects are monitored for all vaccines, including the COVID-19 vaccines. The effects documented to date are short-term and typical of many vaccines (See potential side effects in question #14 above).

21. Does the vaccine affect fertility?
There is no evidence that the COVID-19 vaccine affects fertility. In the safety data from the Pfizer trial, the same proportion of people got pregnant in the vaccine group as the placebo group. Based on this, the vaccine is recommended even if you are planning to get pregnant soon.

22. What do we know about the Johnson & Johnson vaccine?
As of December 28, 2020, large-scale (Phase 3) clinical trials are in progress or being planned for three COVID-19 vaccines in the United States, including the Johnson & Johnson COVID-19 vaccine.

23. What about the new strain out of Europe? What do we know about it being in the US?
In the United Kingdom (UK), a new variant has emerged with an unusually large number of mutations. This variant seems to spread more easily and quickly than other variants. Currently, there is no evidence that it causes more severe illness or increased risk of death. This variant was first detected in September 2020 and it has since been detected in numerous countries around the world, including the United States and Canada.

CDC, in collaboration with other public health agencies, is monitoring the situation closely. CDC is working to detect and characterize emerging viral variants and expand its ability to look for COVID-19 and new variants. At this time, the same strategies to prevent the original COVID-19 strain will also prevent the new strain. This includes mask-wearing, social distancing, and frequent handwashing. Most experts believe that the COVID-19 vaccine will still be effective in preventing the new variant.

24. Is COVID-19 vaccine like flu or chicken pox vaccine? Will have to take it again?
The need for and timing of booster doses for COVID-19 vaccines have not been established. No additional doses beyond the two-dose primary series are recommended at this time.

25. Will the vaccine stay in my body or enter my DNA?
COVID-19 mRNA vaccines do not change or interact with your DNA in any way. Messenger RNA vaccines - also called mRNA vaccines - are the first COVID-19 vaccines allowed to be used in the United States. mRNA vaccines teach our cells how to make a protein that triggers an immune response. The COVID-19 mRNA vaccines work with the body's natural defenses to safely develop immunity to disease. 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. The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions.

26. My health condition isn't addressed here. How do I know if the vaccine is safe for me?
If you have concerns about taking the COID-19 vaccine, talk to your healthcare provider.

27. Do the vaccines work in older adults?
Yes. Older adults should get vaccinated because they are at high risk of hospitalization, illness, and death from COVID-19.

Boston Public Health Commission
1010 Massachusetts Ave, 6th Floor, Boston, MA 02118.
Phone:(617) 534-5395 Email: