Geert Vanden Wijngaert | Bloomberg | Getty Images
A CDC advisory group is considering whether fully vaccinated Americans with compromised immune systems need a booster dose of a Covid vaccine after data shows they are less likely to have antibodies to fight the disease and more likely to have what is known as a breakthrough infection.
Immunocompromised populations account for 44% of hospitalized breakthrough Covid cases – an infection in a fully vaccinated person, according to a slide presented Thursday at the agency’s Advisory Committee on Immunization Practices meeting. The population segment that includes patients with cancer, HIV, or organ transplants makes up only about 2.7% of the adult US population, the presentation said.
Immunocompromised people are more likely to get seriously ill with Covid and have a higher risk of transmitting the virus to family and friends, the agency said.
Studies suggest that a third dose of the vaccine might help people whose immune systems do not respond as well to a first or second dose. Four small studies cited by the CDC showed that 16% to 80% of people with compromised immune systems had no detectable antibodies to Covid after two shots.
Among immunocompromised patients who had no detectable antibody response, 33 to 50% developed an antibody response after receiving an additional dose, according to the CDC.
“New data suggest that an additional dose of COVID-19 vaccine in immunocompromised people increases the antibody response and increases the proportion of those who respond,” read a slide presented at the meeting.
The meeting comes as federal officials say booster doses of the vaccines are not currently required for the general population.
The advisory board cannot recommend additional vaccinations to anyone until the Food and Drug Administration grants full approval of the Covid vaccines or changes emergency approvals.
Other countries such as France are already giving third vaccinations to people with cancer or other immune deficiencies. The CDC group previously said that more vulnerable Americans, such as the elderly or transplant recipients, may need an extra dose.
According to Dr. Dan Barouch, an immunologist at Harvard Medical School who helped develop the J&J vaccine, has urged some doctors to allow the US to allow an additional dose for immunocompromised populations.
“The most difficult ones to vaccinate are people with immunosuppression,” he said, adding that early data shows that a third vaccination could be safe and effective for these populations.
– CNBC’s Rich Mendez and Robert Towey contributed to this article.