In a study published in the Annals of Internal Medicine, Johns Hopkins Medicine researchers say they believe that, for the first time, there is evidence to show 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 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,” said study lead author William Werbel, M.D., an infectious diseases research fellow at the Johns Hopkins University School of Medicine.
People who receive solid organ trans- plants (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 [1] 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 [2], they found the level improved to 54% after the second shot. In both cases, even those trans- plant recipients with antibodies had levels well below what has been typically seen in people with healthy immune systems.
In their latest study [3], 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, M.D., Ph.D., 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.
“These reactions seem acceptable, considering the benefits that vaccines can confer,” said Segev.
Werbel and Segev noted that this study only examined antibody levels, 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.
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.
“Although the third vaccine dose appears to raise the immune response of transplant recipients to higher levels than after one or two doses, these people may still be at greater risk for SARS- CoV-2 infection than the general population who have been vaccinated,” said Werbel. “Therefore, we recommend that transplant recipients and other immuno- compromised people continue to wear masks, maintain physical distancing and practice other Covid-19 safety measures.”
References
[1] Immunogenicity of a Single Dose of SARS-CoV-2 Messenger RNA Vaccine in Solid Organ Transplant Recipients. JAMA. 2021;325(17):1784–1786.
https://doi.org/10.1001/jama.2021.4385
[2] Antibody Response to 2-Dose SARS-CoV-2 mRNA Vaccine Series in Solid Organ Transplant Recipients. JAMA. 2021;325(21):2204–2206. https://doi.org/10.1001/jama.2021.7489
[3] Safety and Immunogenicity of a Third Dose of SARS-CoV-2 Vaccine in Solid
Organ Transplant Recipients: A Case Series. Annals of Internal Medicine.
https://doi.org/10.7326/L21-0282
