Hopkins study: Regular vaccine boosts may help immunocompromised people fight COVID

For people who are the most susceptible to the damaging effects of the coronavirus, regular booster doses of a bivalent COVID-19 vaccine can help them fight the virus, according to a new Johns Hopkins Medicine study .

In the study, published Tuesday in the journal Clinical Infectious Diseases, Hopkins researchers worked with 76 people who had received solid organ transplants and take immunosuppressant medications to prevent their bodies from rejecting the transplants.

This group is among those most at risk of the worst effects of COVID-19, including hospitalization and death, and are especially endangered by the XBB.1.5 subvariant of the omicron strain, which is more transmissible than earlier COVID strains.

The research team found that an organ recipient’s ability to neutralize the XBB.1.5 subvariant wanes about three months following their first shot of a messenger RNA bivalent vaccine, which is designed to enhance immunity to a variety of COVID strains. However, the recipient’s immunity improved with a second booster to about the level it was after their first booster, researchers found.

“This indicates that repeated boosting within six months may play a role in reducing infections, particularly among populations at highest risk, such as [solid organ transplant recipients],” study senior author Dr. Andrew Karaba said in a news release Tuesday from Johns Hopkins Medicine.

Karaba is an assistant professor of medicine at the Johns Hopkins University School of Medicine and an infectious diseases expert with the Johns Hopkins Transplant Research Center.