Tuesday Ward of West View in Pittsburgh receives a COVID-19 booster shot at Allegheny General Hospital on Pittsburgh's North Side on Thursday, Sept. 23, 2021. Credit: Steve Mellon / Pittsburgh Post-Gazette via AP

Americans ages 65 and older should get booster shots, a panel of experts advising the Centers for Disease Control and Prevention said in a unanimous vote Thursday. People over 50 with weakened immune systems were also recommended for an extra dose of the vaccine, the panelists said.

The Advisory Committee on Immunization Practice recommendations came one day after the Food and Drug Administration issued an emergency authorization for people 65 and older, as well as those whose jobs put them at risk of infection, who got the Pfizer Inc.-BioNTech SE shot to receive boosters. An earlier authorization was issued offering extra doses to people with weakened immune systems.

The panel is continuing to vote on recommendations for other categories of people, including those whose workplaces put them at greater risk of infection. CDC Director Rochelle Walensky will have to sign off on the recommendations.

The discussion comes at a crucial time as the U.S. fights a surge of infections driven by the highly contagious delta variant. While the most seriously ill have been primarily the unvaccinated, breakthrough infections among the vaccinated have fueled concerns that the shots’ efficacy may wane over time.

Earlier Thursday, the ACIP members expressed concerns that ongoing resistance to getting vaccinated will prolong the pandemic regardless of whether booster shots are offered as they weighed the extra doses.

“My concern is that we’re just going to keep give booster doses to the vaccinated as different variants come onto the scene, and we’re not going to be able to move forward in truly mitigating the pandemic,” Lynn Bahta, a member from the Minnesota Department of Health, said.

Story by Fiona Rutherford and Robert Langreth, Bloomberg News