Frequently Asked Questions (FAQs) About the COVID-19 Vaccines

Based on research, it is likely that COVID-19 vaccines will prevent people from getting and spreading the virus. The research studies for the Moderna vaccine showed the vaccine prevented COVID-19 in about 95 out of 100 people and severe COVID-19 in 100 out of 100 people.  

The research so far shows that the vaccine is safe and effective.

We think that having COVID-19 may protect you from getting it again, but we are unsure how long. Some patients have had COVID-19 more than once.  It is recommended that people who have had COVID-19 still get the vaccine. 

It is too soon to know how long a vaccine will last. It is currently being researched.  Of the people who have received the vaccine, we know that they have been protected from COVID-19 for at least 4 months.

Both vaccines use tiny parts called messenger RNA (mRNA) carried in very tiny lipid parts.  The two vaccines differ in the way the mRNA is built or the way the lipids are used. The two vaccines are also stored in different ways.

The COVID-19 vaccines prevent or lessen illness from the coronavirus. Both the Pfizer-BioNTech and Moderna vaccines have mRNA, which make the virus’ spike protein. This protein lets the virus attach to cells in our body. When we get the vaccine, we develop antibodies to the spike protein. This stops the virus from attaching to cells when exposed to the virus. Other parts of the body that prevent infection are made active by the vaccines to protect against future COVID-19 infection.

Vaccines for COVID-19 will start out being used under an Emergency Use Authorization (EUA) by the FDA. An EUA makes the vaccine available for public health emergencies. It means that the vaccine is available outside of a research study but is not yet approved. This is the usual first step for a new vaccine. The vaccine can continue to be used as long as people benefit from it. The research continues as it moves toward full approval.

The studies of vaccines included people ages 18 through 85 years old. It worked well for all ages. Studies are needed for people younger than 18 and pregnant women. More studies are going on or being planned. 

Yes, it is especially important for older adults to get the vaccine because they have the highest risk of being very sick or dying from COVID-19. 

Studies show that both vaccines are likely safe and will work for almost everyone. However, they cannot yet be used for children because those studies are not done.

If you are planning to become pregnant, you can receive the vaccine. The FDA also allows pregnant women to receive the vaccine. However, pregnant women were not studied in the vaccine trials, so there is not much information about the use of the vaccine among this group. If you are pregnant, we and the Society for Maternal-Fetal Medicine (SMFM) recommend that you discuss getting the vaccines with your provider. If you are breastfeeding, you can still get the vaccine and do not need to stop breastfeeding.

Yes, some people can get COVID-19 again. It is also not known how long someone is protected from getting the virus again.

It is not possible to get COVID-19 from the vaccines because it only contains a small piece of the virus, not the whole virus. 

Yes, you should continue wearing masks, handwashing, and social distancing after getting the vaccine. This will help bring the pandemic under control. 

Penn Medicine and other hospitals across the country have started receiving a small supply of the vaccine. We have started vaccinating our frontline health care workers who are most at risk, as well as patients who meet the criteria for Phase 1b. Phase 1b includes patients who have one of the following highest risk conditions: 75 years of age or older, cancer, chronic kidney disease, organ transplant, or diabetes mellitus.

The Centers for Disease Control and Prevention (CDC) and the National Academy of Medicine have developed a plan to give the vaccine based on the risk of getting the virus. At first, the vaccine will be given to health care workers and nursing home residents and staff. Next, it will be given to essential workers and then to the general population. The general population will receive the vaccine based on age and medical conditions. People who have a higher chance of getting very sick or dying will receive the vaccine first.

The COVID-19 vaccine will not be mandatory at this time. Once we know more about the vaccine, it’s possible that it will become mandatory. We need to know much more about how long the vaccine protects people and what may happen over time.

Two national pharmacy chains have signed contracts with the federal government to give the vaccine. They have not yet received the supply of the vaccines. Most likely, the first supply to pharmacies will be given to nursing homes and essential workers. The rest of the public will receive it at a later date.