Coronavirus Vaccine: Frequently Asked Questions

Yes. mRNA vaccines, such as Pfizer-BioNTech and Moderna, work differently than other types of vaccines, but they still trigger an immune response inside your body. This type of vaccine is new, but research and development on it has been under way for decades.

The mRNA vaccines do not contain any live virus. Instead, they work by teaching our cells to make a harmless piece of a “spike protein,” which is found on the surface of the virus that causes COVID-19. After making the protein piece, cells display it on their surface. Our immune system then recognizes that it does not belong there and responds to get rid of it. When an immune response begins, antibodies are produced, creating the same response that happens in a natural infection.

In contrast to mRNA vaccines, many other vaccines use a piece of, or weakened version, of, the germ that the vaccine protects against. This is how the measles and flu vaccines work. When a weakened or small part of the virus is introduced to your body, you make antibodies to help protect against future infection.

No. COVID-19 vaccines do not contain microchips. Vaccines are developed to fight against disease and are not administered to track your movement. Vaccines work by stimulating your immune system to produce antibodies, exactly like it would if you were exposed to the disease. After getting vaccinated, you develop immunity to that disease, without having to get the disease first.

Learn more about the ingredients in the COVID-19 vaccinations authorized for use in the United States.

Learn more about how mRNA COVID-19 vaccines work.

No. Receiving a COVID-19 vaccine will not make you magnetic, including at the site of vaccination which is usually your arm. COVID-19 vaccines do not contain ingredients that can produce an electromagnetic field at the site of your injection. All COVID-19 vaccines are free from metals.

Learn more about the ingredients in the COVID-19 vaccinations authorized for use in the United States.

No. Vaccine shedding is the term used to describe the release or discharge of any of the vaccine components in or outside of the body. Vaccine shedding can only occur when a vaccine contains a weakened version of the virus. None of the vaccines authorized for use in the U.S. contain a live virus. mRNA and viral vector vaccines are the two types of currently authorized COVID-19 vaccines available.

Learn more about mRNA and​ viral vector COVID-19 vaccines.

Yes. If you are trying to become pregnant now or want to get pregnant in the future, you may get a COVID-19 vaccine when one is available to you.

There is currently no evidence that COVID-19 vaccination causes any problems with pregnancy, including the development of the placenta. In addition, there is no evidence that female or male fertility problems are a side effect of any vaccine, including COVID-19 vaccines.

No. COVID-19 vaccines do not change or interact with your DNA in any way. Both mRNA and viral vector COVID-19 vaccines deliver instructions (genetic material) to our cells to start building protection against the virus that causes COVID-19. However, the material never enters the nucleus of the cell, which is where our DNA is kept.

Learn more about mRNA and​ viral vector COVID-19 vaccines.

No. None of the authorized and recommended COVID-19 vaccines cause you to test positive on viral tests, which are used to see if you have a current infection.​

If your body develops an immune response to vaccination, which is the goal, you may test positive on some antibody tests. Antibody tests indicate you had a previous infection and that you may have some level of protection against the virus.

Learn more about the possibility of COVID-19 illness after vaccination