A third dose of Covid vaccine may help protect immunocompromised patients, small study suggests

A third dose of Covid vaccine may help protect immunocompromised patients, small study suggests Some organ transplant patients saw a boost in antibody levels after receiving a third dose of a Covid-19 vaccine. NBC News

A third dose of a Covid-19 vaccine may boost protection for some people with weakened immune systems, according to a study published Monday in the Annals of Internal Medicine.

The study, from researchers at Johns Hopkins University, included 30 organ transplant recipients, all of whom had been fully vaccinated with two doses of an mRNA vaccine, either Pfizer-BioNTech or Moderna. Because organ transplant recipients must take immune-suppressing medications to ensure that their body does not reject the transplant, there’s concern that they may not develop robust responses to the vaccines, leaving them vulnerable to Covid-19.

Indeed, despite being fully vaccinated, the vast majority of patients in the study — 24 patients — had no antibodies against the coronavirus, and six patients had only low levels.

So, the researchers gave them a third dose of the vaccine, either Pfizer, Moderna or Johnson & Johnson. About two weeks later, their antibody levels were measured again. In patients who had no antibodies to begin with, eight had an increase following their third dose of the vaccine. And in the six patients who started off with low levels, all had an increase in antibodies against the coronavirus.

Though the study was small, the findings could be important for millions of Americans who are immune-compromised and still vulnerable to Covid-19, even after being vaccinated. According to the United Network for Organ Sharing, more than 17,000 transplants were performed in the first five months of 2021 alone.

“To me the main message here for transplant patients and immunosuppressed patients is a message of hope,” said Dr. Dorry Segev, an author of the study and associate vice chair for research and professor of surgery at Johns Hopkins University. ...