For Transplant Recipients, A Third COVID Vaccine Dose May Offer Better Protection

Researchers at Johns Hopkins Medicine have shown that three doses of vaccine against SARS-CoV-2 — the virus that causes COVID-19 — increase antibody levels more than the standard two-dose regimen for people who have had solid organ transplants. The researchers say this finding suggests that booster doses should be explored for those who are immunocompromised. Credit: Image created by ME Newman, Johns Hopkins Medicine, featuring public domain images and background artist’s rendition of SARS-CoV-2 courtesy of the U.S. Centers for Disease Control and Prevention

Johns Hopkins Medicine researchers say study findings suggest booster doses should be explored for those who are immunocompromised.

In a study published June 15, 2021 in the Annals of Internal Medicine, Johns Hopkins Medicine researchers say they believe there is the first-ever evidence showing that three doses of vaccine increase antibody levels against SARS-CoV-2. — the virus that causes COVID 19 — more than the standard two-dose regimen for people who have had solid organ transplants.

“Our findings suggest that clinical trials are warranted to determine whether transplant recipients should receive COVID-19 vaccine booster doses as standard clinical practice, similar to what is currently being done with hepatitis B and flu vaccinations for this population,” said lead author William Werbel of the study, MD, an infectious disease researcher at Johns Hopkins University School of Medicine.

People undergoing solid organ transplants (such as hearts, lungs, and kidneys) often have to take medications to suppress their immune systems and prevent rejection. Such regimens may interfere with a transplant recipient’s ability to make antibodies against foreign substances, including the protective ones produced in response to vaccines.

In the first of two previous studies, the researchers showed that only 17% of participating transplant recipients produced enough antibodies after one dose. Then in the second study, they found that levels improved to 54% after the second injection. In both cases, even those transplant recipients with antibodies had levels well below those typically seen in people with healthy immune systems.

In their latest study, the researchers evaluated 30 organ transplant recipients who received a third dose of one of three vaccines – Johnson & Johnson/Jansen, Moderna or Pfizer/BioNTech – between March 20 and May 10, 2021. They had previously received two doses of the Moderna or the Pfizer/BioNTech vaccine. The median age of the study participants was 57, 17 were female and one identified as non-white. No study participant reported illness prior to vaccination or a positive test for SARS-CoV-2. All took multiple immunosuppressive drugs to prevent rejection of their transplanted organs.

“Our findings revealed that a third of participants with negative antibody levels and all with low positive levels before the booster increased their immune response after a third vaccine dose,” said lead author Dorry Segev, MD, Ph.D., de Marjory K. and Thomas Pozefsky. professor of surgery and epidemiology and director of the Epidemiology Research Group in Organ Transplantation at Johns Hopkins University School of Medicine.

One week after receiving their third vaccine dose, 23 study participants completed a questionnaire about side effects. The reactions were generally mild or moderate, with one participant reporting severe arm pain and another severe headache. No participant reported fever or an allergic reaction. There was one case of mild organ rejection during the study.

“These responses seem acceptable, given the benefits vaccines can provide,” Segev says.

Werbel and Segev note that only antibody levels were examined in this study and that future research is needed to see if the increased immune response after a third vaccine dose is associated with lower SARS-CoV-2 infection rates.

“While the third vaccine dose appears to increase the immune response of transplant recipients to higher levels than after one or two doses, these people may still be at greater risk of SARS-CoV-2 infection than the general population that has been vaccinated.” Werbel says. “We therefore recommend transplant recipients and other immunocompromised people to continue wearing masks, maintain physical distancing and take other COVID-19 safety measures.”

Reference: “Safety and immunogenicity of a third dose of SARS-CoV-2 vaccine in solid organ transplant recipients: a case series” by William A. Werbel, MD, Brian J. Boyarsky, MD, PhD, Michael T. Ou, BS, Allan B. Massie, PhD, Aaron AR Tobian, MD, PhD, Jacqueline M. Garonzik-Wang, MD, PhD, and Dorry L. Segev, MD, PhD, June 15, 2021, Annals of Internal Medicine.
DOI: 10.7326 / L21-0282

In addition to Werbel and Segev, the Johns Hopkins Medicine research team includes Brian Boyarsky, Michael Ou, Allan Massie, Aaron Tobian and Jacqueline Garonzik-Wang.

The study was supported by a donation from the Ben-Dov family; grants F32DK124941 and K23DK115908 from the National Institute of Diabetes and Digestive and Kidney Diseases; grant K24AI144954 from the National Institute of Allergy and Infectious Diseases; and grant gSAN-201C0WW from the Transplantation and Immunology Research Network of the American Society of Transplantation.

None of the authors have any financial disclosures or conflicts of interest related to this study.