Johns Hopkins Medicine researchers say study findings suggest SARS-CoV-2 vaccine booster doses should be investigated for those who are immunocompromised.
Published in the Annals of Internal Medicine, the study shows 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 received solid organ transplants.
“Our findings suggest clinical trials are warranted to determine if transplant recipients should receive COVID-19 vaccine booster doses as standard clinical practice, similar to what is currently done with hepatitis B and influenza vaccinations for this population,” says study lead author William Werbel, MD, Infectious Diseases Research Fellow at the Johns Hopkins University School of Medicine.
People who receive solid organ transplants (such as hearts, lungs and kidneys) often must take drugs to suppress their immune systems and prevent rejection. Such regimens may interfere with a transplant recipient’s ability to make antibodies to 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 the participating transplant recipients produced sufficient antibodies after one dose. Then, in the second study, they found the level improved to 54% after the second shot. In both cases, even those transplant recipients with antibodies had levels well below what has been 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 either the Moderna or Pfizer/BioNTech vaccine. The median age of the study participants was 57; 17 were women and one identified as non-white. No study participant reported an illness prior to vaccination or a positive test for SARS-CoV-2. All were taking multiple immunosuppressive medications to prevent rejection of their transplanted organs.
“Our findings revealed that a third of the participants who had negative antibody levels and all who had low positive levels before the booster increased their immune response after a third vaccine dose,” says study senior author Dorry Segev, MD, PhD, the Marjory K. and Thomas Pozefsky Professor of Surgery and Epidemiology and director of the Epidemiology Research Group in Organ Transplantation at the Johns Hopkins University School of Medicine.
A week after receiving their third vaccine dose, 23 study participants completed a questionnaire about adverse effects. Reactions were generally mild or moderate, with one participant reporting severe arm pain and another a severe headache. No participant reported fever or an allergic reaction. There was one case of mild organ rejection during the study.
