COVID-19 Vaccination FAQs

Vaccination at Yale

Which COVID-19 vaccines are available?

Three vaccines are currently available for administration under emergency use authorization by the FDA:

Two mRNA vaccines- the Pfizer vaccine (a 2-shot series given three weeks apart) and the Moderna vaccine (a 2-shot series but given 4 weeks apart)

Johnson and Johnson (J&J) vaccine which is an adenovirus vaccine.

Yale Health will administer the vaccine that is received from the state. It is important to note that the vaccines, in general, are not interchangeable and both doses must be from the same manufacturer.

Will I have the ability to choose which COVID-19 vaccine I get? 

No, not at this time. We distribute the COVID-19 vaccines as we receive them from the CT Department of Health and do not have the ability to request specific manufacturers. However, for the 2-dose Pfizer and Moderna vaccines, we will ensure that your second vaccine is available for your scheduled follow-up visit. Given the limited supply of COVID-19 vaccines across the U.S, we cannot control the type and amount of COVID-19 vaccines that we receive. Therefore, we encourage you to take any one of the three vaccines now available.

All three COVID-19 vaccines have been shown to reduce the risk of becoming infected with COVID-19 and being hospitalized. Most importantly, all have been shown to eliminate the risk of developing severe disease and death due to COVID-19.

Is the COVID-19 vaccination mandatory for Yale employees or Yale healthcare workers?

No, not at this time. Vaccination against COVID-19 with either of the approved vaccines is strongly recommended. By accepting the vaccine as it becomes available to you, you will be protecting yourself, your loved ones and your community.

How is the vaccine distribution being prioritized?

The Centers for Disease Control have issued guidelines and the Connecticut Department of Public Health is structuring vaccination delivery in required phases that align with those guidelines. The university is following the state eligibility requirements as we receive vaccine distributions. 

How will I be notified if I am eligible for the vaccination?

You will receive an invitation to schedule a vaccination by email sent to the address associated with your MyChart account. The email notification will include a link to schedule a vaccination appointment in MyChart. (Those who do not currently have a MyChart account should consider setting up an account in advance of receiving the notification.)  

What is the Yale COVID-19 Vaccine Standby Program?

At the end of each vaccine clinic, there are typically extra vaccine doses due to missed or canceled appointments, or additional vaccine left in a vial.  The extra doses must be used within 6 hours. To avoid wasting doses, each clinic needs a small number of individuals who can be available at the last minute should extra vaccine be available.

The Yale COVID-19 Vaccine Program has developed a vaccine standby process to ensure that all COVID vaccine doses are used at the end of each vaccination clinic. Learn more about the standby program. 

Can I receive my vaccine on work time?

Yes. We are committed to making access as accommodating as possible. Please notify your manager when you receive the email invitation to schedule the vaccine. You and your manager will work together to select a scheduled appointment time for receiving the vaccine that provides sufficient coverage in your unit.

Where is vaccination being administered?

COVID-19 vaccinations are being administered at the Lanman Center. Once you have your appointment, read these directions on how to access the Lanman Center vaccination site.

Does the COVID-19 vaccination cost anything?

We are offering vaccines to the Yale community at no cost. However, vaccine providers for the general public may be able to charge administration fees for performing vaccinations.

How can I learn more?

Visit the CDC’s vaccine website, the Connecticut Department of Public Health website or ask your healthcare provider. Yale Health will be updating and distributing more generally asked questions and answers as more information becomes available.


How do the Pfizer and Moderna vaccines work?

These vaccines consist of genetic material called mRNA encased in tiny particles that shuttle it into our cells. From there, it stimulates the immune system to make antibodies that protect against the virus. These vaccines do not have any impact on our genes. The vaccine material breaks down in the body shortly after it is taken into our cells.

How does the J&J COVID-19 vaccine work? 

The J&J vaccine involves a complex of an adenovirus (a common virus that can cause mild respiratory illnesses) and COVID-19 spike protein. The adenovirus acts as a shuttle (or vector) to transport the COVID-19 spike protein into human cells.  Our immune system then reacts against the spike protein to develop antibodies which then protect us from COVID-19 infection.

It is important to note that the adenovirus-spike protein complex has been altered so that:

  • It is unable to replicate and cannot cause infection;
  • It does not have any impact on our genes; and
  • It breaks down in the body shortly after it is taken into our cells.

Which vaccine is the most effective? I’ve heard the J&J efficacy percentages are lower than the other two vaccines.

All authorized COVID-19 vaccines demonstrated efficacy (range 65 to 95%) against symptomatic lab-confirmed COVID-19 and high efficacy against COVID-19 severe enough to require hospitalization. The Phase 3 clinical trials for each vaccine differed in calendar time and geography. This means there were different circulating variants and incidence of disease when the studies were done. No studies have been done comparing the vaccines with each other. Safety and side effect data are comparable for all. The Advisory Committee on Immunization Practices states no preference for any of the three authorized vaccines.

The following table compares the three COVID-19 vaccines currently available in the U.S. It is important to note that most vaccine side effects from all three vaccines resolved in 1-2 days post-vaccination:

  Pfizer Moderna J&J
Number of shots 2 2 1
Days between shots 21 28 NA
Contains live virus No No No
Contains latex No No No
Contains preservatives No No No
Age authorized 16 years and older 18 years and older 18 years and older
Effectiveness preventing hospitalizaiton & death 100% 100% 100%
Common side effects

injection site pain



muscle pain

joint pain

injection site pain



muscle pain

joint pain

injection site pain



muscle pain

Are the vaccines safe?

All data currently available indicate that the vaccine is safe. While they may be new, the authorized COVID-19 vaccines have been tested in large clinical trials. Thus far, no serious long-term side effects have occurred, and any side effects that do occur are not severe and occur within six weeks of vaccination. The FDA will continue to monitor for any rare safety issues.

Based upon data from these trials, the CDC and FDA, including an independent group of experts from the CDC’s Advisory Committee of Immunization Practices (ACIP), have found these vaccines to be safe and effective. While no medication or vaccine is without side effects, the COVID-19 vaccines are similar to other approved vaccines and side effects tend to be mild or moderate and last a couple of days. Millions of people in the United States have already received COVID-19 vaccines under the most intense safety monitoring in U.S. history.

Despite the large size of clinical trials, some rare or long-term side effects may not be seen. Fortunately, monitoring does not stop when the trials end. The United States has systems, such as VAERS, v-safe and MedWatch, to continuous monitor medications and vaccines for safety issues. If an issue is detected, experts take immediate action to determine if it is related to the vaccine and how best to proceed. Learn more about COVID-19 vaccine safety monitoring.

Should you have more questions, please contact a healthcare provider for more information.

Can receiving the vaccination give someone COVID-19?

No. The vaccine does not contain live or dead versions of the virus, so it cannot give someone COVID-19.

What are possible side effects of the vaccine?

Common side effects include:

  • sore arm or pain and redness at the injection site
  • swollen lymph nodes in the underarm on the same side as the injection site
  • chills or fever
  • fatigue, body aches or feeling run down
  • headache
  • nausea, vomiting or diarrhea in the first 72 hours

Symptoms typically go away on their own within 1-2 days  and can be relieved with over the counter medications. Swollen lymph nodes may persist up to about 10 days. These side effects are a sign that your immune system is working to develop antibodies to COVID-19. 

How can I tell if side effects are from the vaccine or from actual COVID-19 infection?

The vaccine does not cause respiratory symptoms (cough/runny nose) or a loss of taste or smell, which are sometimes seen with a true COVID-19 infection. For these symptoms or anything apart from mild side effects, you should contact your provider for medical advice and possible COVID-19 testing.

How long will the vaccine protect those that receive it?

Pfizer reports that the vaccine is ninety-percent effective. Moderna reports that their vaccine is ninety-four-percent effective. While the studies haven’t indicated how long protection will last, the FDA predicts it to be effective for several months and possibly a year. Vaccine experts are continuing to study the virus and vaccine to learn more.

Are you immune to COVID-19 after recovering from it?

The extent to which antibodies that develop in response to SARS-CoV-2 infection are protective is still under study. If these antibodies are protective, it’s not known what antibody levels are needed to protect against reinfection. Therefore, even those who previously had COVID-19 can and should receive the COVID-19 vaccine.

Why should someone get the vaccine even though they are doing other things such as wearing a mask, washing their hands often and practicing physical distancing?

Stopping a pandemic requires using all the tools available. Vaccines work with your immune system so your body will be ready to fight the virus and reduce or eliminate illness if you are exposed. Other steps, like covering your mouth and nose with a mask and staying at least six feet away from others, help reduce your chance of being exposed to the virus or spreading it to others.

Do the COVID-19 vaccines protect against the new variants of the virus?

Viruses constantly change through mutation, and new variants of a virus are expected to occur over time. Sometimes new variants emerge and disappear. Other times, new variants emerge and persist. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic, primarily from the United Kingdom, South Africa and Brazil. These variants seem to spread more easily and quickly than other variants, which may lead to more cases of COVID-19.

Scientists are working to learn more about how easily they spread, whether they could cause more severe illness, and whether currently authorized vaccines will protect people against them. So far, studies suggest that antibodies generated through vaccination with currently authorized vaccines recognize these variants. This is being closely monitored by the Centers for Disease Control and Prevention and more studies are underway.

For these reasons, it is essential to limit the spread of the virus by continuing to wear a mask that covers your mouth and nose, keep physical distance, wash your hands, get regularly tested, participate in contact tracing and get the COVID-19 vaccine when it is available to you.

Does the flu vaccine also protect you from COVID-19?

No. The coronavirus (COVID-19) and the flu are completely different. The flu vaccine does not protect you from becoming infected with COVID-19, so you should get both vaccines. One of the benefits from getting a flu vaccine in addition to the COVID-19 vaccine, is that a recent study suggested that people who received flu vaccine faced a lower risk for being hospitalized if they got COVID-19.

Can we stop wearing masks once vaccinations are given?

No. While the vaccine is extremely effective, a small percentage of those who receive it may not be fully protected, so we need to continue to wear masks and other PPE, social distance and use other precautions. Because it will take many months to vaccinate a large portion of the population, COVID-19 will continue to circulate.  Environmental Health and Safety has updated its website to reflect this guidance and to provide additional information of importance for the Yale community.