NEW YORK — A Centers for Disease Control and Prevention advisory panel on Thursday voted to recommend a third Pfizer-BioNTech COVID-19 shot for those over 65 and certain groups with underlying medical conditions.

In a series of votes, the Advisory Committee on Immunization Practices said it favored booster shots at least six months after the standard two-dose regimen for all people 65 years old and older, as well as those 18 to 64 with underlying medical conditions that put them at high risk for COVID-19.

Booster shots of the vaccine, which goes by the brand name Comirnaty, could be available this week, after CDC Director Rochelle Walensky formally adopts the group’s recommendations. The guidance passed by a majority vote on Thursday afternoon following a two-day meeting of the CDC’s Advisory Committee on Immunization Practices.

“I appreciate your meticulous review of the data available from CDC’s own cohort studies, from FDA’s review of Pfizer’s studies, and from public health partners and institutions around the world,” CDC Director Rochelle Walensky told the group as it began its meeting Thursday afternoon.

“These data are not perfect, yet collectively they form a picture for us, and they are what we have in this moment, to make a decision about the next stage in this pandemic,” added Walensky.

Long-term care facility residents also were included.

The panel voted against allowing the booster shots for those with frequent occupational and institutional exposure to the virus, such as healthcare workers.