An advisory panel for the Centers for Disease Control and Prevention (CDC) weighed whether to recommend booster COVID-19 vaccines to people who are immunocompromised during a Thursday meeting.
A CDC epidemiologist presented the Advisory Committee on Immunization Practices (ACIP) with small studies involving immunocompromised people receiving a third shot that suggested the dose “may enhance antibody response in some.”
But the panel did not make an official recommendation on booster shots for the population as its experts are still in the process of reviewing available data.
The emerging data across four studies showed that among the immunocompromised people who had no antibody response to the initial two vaccine doses, 33 to 50 percent developed an antibody response with an additional dose.
About 2.7 percent of American adults are considered immunocompromised, including people with cancer, those with HIV and those who have had organ or stem cell transplants.
People with weaker immune systems are more likely to fall severely ill from COVID-19, a fact that has prompted calls for the at-risk group to get additional COVID-19 shots.
Sara Oliver, a medical epidemiologist with CDC's National Center for Immunization and Respiratory Diseases who presented the data, noted that antibody response data does not “tell the full story” on vaccine protection but still offers the panel information.
Several ACIP voting members and liaisons expressed concerns that immunocompromised patients are taking matters into their own hands by getting additional shots instead of waiting for the panel’s recommendation.
“I am concerned about them doing this kind of in an unsupervised fashion,” said Camille Kotton, a transplant-medicine physician at Massachusetts General Hospital. “But as it is right now, due to regulatory issues we are not allowed to recommend additional doses, so patients are really just doing what they think is best.”
“Our hands are really tied with the current regulatory situation, and that is a challenge,” she added.
Pablo Sanchez, a professor of pediatrics at Ohio State University, acknowledged that they “obviously need more data” on how the booster shots work for people with specific immunocompromised conditions.
But he added, “It seems to me that the issue is almost running away from us already.”
There is not another ACIP meeting currently scheduled although the panel is expected to meet in August.
In the meantime, the CDC advised that fully vaccinated immunocompromised people continue to take safety precautions including wearing masks, avoiding crowds and social distancing.
Other studies have shown immunocompromised people make up a higher proportion of hospitalized breakthrough cases, including 44 percent in a U.S. study and 40 percent in an Israeli study. Breakthrough cases occur among fully vaccinated individuals.
Additional research, presented by Oliver, has indicated that immunocompromised people likely have less antibody response to mRNA COVID-19 vaccines than other healthy vaccine recipients.