'An important win': COVID-19 booster dose enhances protection for transplant recipients

A third dose of the Moderna COVID-19 vaccine substantially improved protection for transplant recipients, according to findings published in the New England Journal of Medicine.

The data are from the first-ever randomized, placebo-controlled trial of a COVID-19 vaccine booster dose in transplant recipients, according to a press release.

“We knew from previous studies that two doses were not enough to produce a good immune response against COVID-19 in transplant patients,” Deepali Kumar, MD, director of transplant infectious diseases in the Ajmera Transplant Centre at the University Health Network in Toronto, said in the press release. “Based on our study, a third dose of the COVID-19 vaccine is definitely the best way to increase protection in transplant recipients.”

Kumar and colleagues conducted a randomized, double-blind, placebo-controlled study of 120 organ transplant patients who had previously received two doses of the Moderna COVID-19 vaccine. No patient enrolled had previously been diagnosed with COVID-19. Half of the patients were randomly assigned to receive a third vaccine dose while the other half were assigned to placebo. The median age of patients was 66.6 years, and the median time between transplantation and a third vaccine dose was 3.16 years. The primary outcome was antibody response level of at least 100 U/ml against a spike protein of the virus at month 4.

The researchers reported that an antibody response of at least 100 U/ml at month 4 was detected in 55% of patients who received a third dose of the Moderna vaccine compared with 18% of those who received placebo (P < .001). In addition, 60% of the third-dose cohort developed neutralizing antibodies compared with 25% of the placebo cohort (RR = 2.4; 95% CI, 1.5-4).

The third dose also appeared to be safe, with no grade 3 or 4 adverse events or cases of acute rejection reported, according to the researchers.

“This is an important win for our patients because the results are quite conclusive,” Atul Humar, MD, medical director of the Ajmera Transplant Centre and joint senior author of the clinical trial, said in the press release. “The third dose was safe and well tolerated and should lead to a change in practice of giving third doses to this vulnerable population.”

Editor’s note: On Aug. 13, the CDC’s Advisory Committee on Immunization Practices recommended a third dose of COVID-19 vaccine in patients who are moderately or severely immunocompromised.

References:

Kumar D, et al. N Engl J Med. 2021;doi:10.1056/NEJMc2111462.

Newswise. World-first COVID vaccine booster randomized clinical trial in transplant patients proves third shot is very effective. https://www.newswise.com/coronavirus/world-first-covid-vaccine-booster-randomized-clinical-trial-in-transplant-patients-proves-third-shot-is-very-effective. Accessed Aug. 12, 2021.