The University of Maryland Medical Center understands that transplant patients — both those already transplanted and those awaiting one — have specific questions related to the COVID-19 vaccine.

We compiled your questions and our experts answer them.

Should transplant patients get vaccinated?

Yes. We strongly recommend transplant recipients get the COVID-19 vaccine as vaccination can prevent or decrease the severity of infection. Learn more about the vaccines available on the CDC's website.

Why do transplant patients need three doses of mRNA vaccine for their initial (primary) vaccine series?

Initial studies looking at how well COVID-19 mRNA vaccines (Pfizer and Moderna) worked in transplant patients found that antibody responses after two doses of mRNA vaccine were much lower in transplant patients when compared to people with healthy immune systems. A clinical trial studying a third dose was performed and showed significantly increased antibody responses compared to two doses.

Following these results, the CDC recommended all transplant patients complete three doses of mRNA vaccine as part of their primary vaccine series.

The three-dose primary vaccine series only applies to the mRNA COVID-19 vaccines. If a transplant patient chooses the Novavax vaccine for their primary vaccine series then only two doses are needed to complete the primary series.

Do transplant patients need booster doses of COVID-19 vaccines?

The CDC recommends all eligible people receive a bivalent booster. The bivalent booster is an updated mRNA vaccine that contains components that help protect against the original SARS-CoV-2 virus and against the Omicron variants of SARS-CoV-2. Transplant patients should receive a bivalent booster at least two months following completion of the initial three-dose primary series of mRNA vaccines or 2 months after their last booster dose.

In April 2023, the CDC updated their recommendations and now allow an additional dose of the bivalent vaccine booster for patients that are immunocompromised. (Please see the CDC's recommendations for people who are immunocompromised.)

When should transplant patients get vaccinated?

If you are on the transplant waitlist, it is better to complete the primary vaccine series (and any recommended booster doses) before your transplant. You should talk about vaccination timing with your transplant team.

If you had a transplant, we recommend waiting at least two months after your transplant surgery before getting the vaccine. You should talk about vaccination timing with your transplant team.

Should transplant patients get the vaccine if they have already had COVID-19?

Yes! Patients with weakened immune systems (and even healthy people) can be re-infected with SARS-CoV-2. People who are vaccinated after COVID-19 are less likely to develop a new infection compared to those who remain unvaccinated.

If you developed COVID-19, you should wait until all your symptoms are improved before receiving a vaccine. The optimal timing of vaccination after COVID-19 infection is still being investigated. Talk with your transplant team about how long to wait for vaccination once you have recovered.

Is it okay for transplant patients to get two different vaccines?

The CDC's recommendations about mixing doses are the same for transplant patients as it is for the general population.

Are side effects of COVID-19 vaccines different in transplant patients?

Review of safety data among transplant patients shows that transplant patients have equal rates of common side effects as healthy individuals. These include headache, fever, fatigue, and injection site pain, which typically occur 1-3 days after vaccination. Importantly, there is no increased risk of organ rejection following COVID-19 vaccination.

In a study of 741 transplant patients who received both doses of mRNA vaccines, none had severe side effects.

mRNA COVID-19 vaccines in very rare cases have been linked to inflammation of the heart muscle, or myocarditis. This typically has been seen in young males ages 18 to 24. The risk is very low with 30-40 cases per million doses in the 12-29 age group. The majority of cases have been mild with most individuals recovering. Because myocarditis can also occur with COVID-19 infection, COVID-19 vaccine continues to be recommended by the CDC to prevent severe forms of infection.

Please see the Food and Drug Administration EUA Fact Sheets for each vaccine for more information about side effects.

How well do the vaccines work in transplant patients?

These vaccines and likely other vaccines (for example, the flu shot) work less well in transplant patients than in healthy people. We expect this is because transplant medicines weaken the immune system.

Reports looking at COVID-19 infections in solid organ transplant recipients who were vaccinated show that transplant patients that are fully vaccinated have a lower risk for infection and severe disease when compared to unvaccinated transplant patients However, rates of infection in vaccinated transplant recipients are higher when compared to vaccinated individuals with normal immune systems.

In one study, fully vaccinated transplant recipients' risk of dying from COVID-19 infection was 40 percent lower than unvaccinated transplant recipients' risk of dying.

We can also see how well a vaccine works by measuring antibodies. A blood test can measure antibodies after vaccination. We assume that having a high number of antibodies protects against infection. We do not know how much antibody is needed to protect people from severe infection or death from COVID-19.

After completing the three-dose primary COVID-19 vaccine series about 70 percent of all transplant patients make antibodies. Some studies have shown that additional doses of COVID-19 vaccine can increase antibodies further. However, when compared to healthy people, transplant patients make fewer antibodies.

Even if antibody levels are low, there is a chance the vaccine may still protect from severe infection.

Should transplant patients get antibody testing after receiving COVID-19 vaccination?

No. The CDC does not recommend checking antibody levels after your COVID-19 vaccination.

Antibody testing is approved to see if there is a COVID-19 infection. Right now, we do not know what level of antibody is necessary for protection against infection or severe disease. Also, antibody testing does not measure all the different components of the immune response needed to protect against COVID-19.  People can still have protection against severe forms of COVID-19 even if antibody levels are low.

Will I still have to wear a mask and keep my distance after I get the vaccine?

As a transplant patient, you should be more careful than everyone else even if you are fully vaccinated or have received booster doses of the COVID-19 vaccine. This is because your risk of infection is still greater than the average person even if you are fully vaccinated. While it may be okay to not wear a mask amongst your close contacts (especially if they are also vaccinated), we recommend transplant patients should:

  • Wear a mask even though masking requirements have been removed for the general public
  • Practice social distancing, especially when gathering indoors with people that are not your close contacts
  • Avoid large crowds
  • Wash your hands often

These safety measures are especially important when COVID-19 activity in the community is increased.