Science’s COVID-19 reporting is supported by the Heising-Simons Foundation.
A few months ago, transplant surgeon Dorry Segev was despondent about how COVID-19 vaccines were performing in patients like his, who have a donated organ and take powerful drugs to suppress their immune system. After one dose of a highly effective messenger RNA (mRNA) vaccine, for example, just 17% of those patients churned out protective antibodies against the pandemic coronavirus, and after the standard two doses, only 54% did. The very medications his patients took to protect their transplanted organ precluded them from mounting a healthy immune response after the vaccine. Even people who did make the antiviral antibodies often had very low levels, raising questions about how well they were shielded from COVID-19.
But now Segev, at Johns Hopkins University, has become cautiously optimistic. He and his colleagues have found that a third dose of vaccine may help: Among 24 organ transplant patients who had no antibodies after two doses, eight people generated protective antibodies after they sought out a third on their own. Six people who had few antibodies against the coronavirus after two doses all wound up with high levels after a third shot, the researchers reported today in the Annals of Internal Medicine. Although Segev didn’t conduct a systematic study—the 30 patients got combinations of different vaccines at different time intervals—“this gives hope, which is critical right now,” he says. “There is some encouraging evidence that we will be able to help the immune system do what it needs to do.”