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Vaccine Safety

The UFT has compiled some frequently-asked questions about the safety of the available vaccines for COVID-19. To see more details about how the UFT vaccine program works, visit our vaccine information page

Is the vaccine safe? 

Yes. The COVID-19 vaccines have gone through large clinical studies involving tens of thousands of people of various ages, races and ethnicities. The Food and Drug Administration and independent organizations closely reviewed the evidence from those studies before the government gave emergency use authorization.

How many doses need to be taken of the COVID-19 vaccines to be effective?

The two authorized vaccines, Pfizer and Moderna, both need two shots to be effective. The first shot starts building protection. A second shot 21 to 28 days later, depending on the vaccine, is needed to get the most protection the vaccine has to offer.

How well do the vaccines work? 

In clinical studies, both vaccines were more than 94% effective at protecting participants from COVID-19 once both doses were received. 

Will a COVID-19 vaccination protect me from getting sick with COVID-19?

Yes. COVID-19 vaccination works by teaching your immune system how to recognize and fight the virus that causes COVID-19, and this protects you from getting sick with COVID-19.

Are there side effects from the COVID-19 vaccines? 

It is normal to experience side effects after the first or second dose of the vaccine, which is also a sign that the body is building immunity. Common side effects include soreness in the arm where you received your immunization, tiredness or a headache. Other side effects from COVID-19 vaccination could include flu-like symptoms and fever, but these should go away in a few days. Learn more about what side effects to expect and get helpful tips on how to reduce pain and discomfort after your vaccination. If you experience any side effects after taking the vaccine, contact your health care provider as soon as possible. 

Can I get COVID-19 from the vaccine? 

No. None of the COVID-19 vaccines contain the live virus that causes COVID-19, so receiving the vaccine cannot make you sick with COVID-19. 

How long will it take the vaccines to work once administered?

It typically takes a few weeks for the body to build immunity after vaccination. It is possible a person could be infected with the virus that causes COVID-19 just before or just after vaccination and still get sick because the vaccine has not had enough time to provide protection. 

I had COVID-19 already. Do I need the vaccine?

Since it is possible to get COVID-19 again, you should be vaccinated. The vaccine may also boost the protection your body has already built up. However, if you tested positive for COVID-19 within the past 90 days, consider waiting to get the vaccine, since the vaccine is scarce and it is very unlikely that you will get COVID-19 again during this time. Talk to your health care provider if you have more questions.

When I get vaccinated, can I stop social distancing and wearing a face mask?

No. Experts need to understand more about the protection that COVID-19 vaccines provide before deciding to change recommendations on steps everyone should take to slow the spread of the virus. Other factors, including how many people get vaccinated and how the virus is spreading in communities, will also affect this decision. You should continue COVID-19 safety precautions, such as wearing a mask, social distancing, washing your hands, and staying home if you feel sick. 

I have allergies and am concerned about complications from the vaccine. Should I get immunized right now? 

Your health care provider knows your personal medical history best, so we recommend you speak with your provider before scheduling an appointment. 

Should women who are pregnant or breastfeeding receive the vaccine?

Pregnant and breastfeeding women should consult with their obstetricians and pediatricians about whether to get the vaccine. Until findings are available from clinical trials and additional studies, only limited data are available on the safety of COVID-19 vaccines administered during pregnancy.

How do mRNA vaccines like the Pfizer and Moderna vaccines work? 

Messenger RNA (mRNA) vaccines make proteins from the coronavirus, which can stimulate the immune system. While the immune protection from these vaccines may last for months or perhaps even years, their mRNA does not — it is destroyed by our cells within days.  Learn more about how COVID-19 mRNA vaccines work. ​

Can the vaccine change my genes or DNA?

No, this vaccine does not have any impact on your genes or DNA. Messenger RNA (mRNA) vaccines teach our cells how to make a protein that triggers an immune response. The mRNA from a COVID-19 vaccine never enters the nucleus of the cell, which is where your DNA is kept. This means the mRNA cannot affect or interact with your DNA in any way and breaks down in the body shortly after it is taken up into our cells. 

To learn more about the COVID-19 vaccines, talk to your health care provider, call 311 within New York City, or visit nyc.gov/covidvaccine or cdc.gov/covidvaccine.