16- and 17-year-olds are now eligible for the Pfizer-BioNTech COVID-19 vaccine booster, following the Food and Drug Administration’s expansion of its emergency use authorization and the Centers for Disease Control and Prevention’s similar recommendation on Thursday.

The expansion of eligibility to 16- and 17-year-olds follows an earlier approval of the booster for all adults in mid-November, and rising concern about the spreading Omicron variant.

“Although we don’t have all the answers on the Omicron variant, initial data suggests that COVID-19 boosters help broaden and strengthen the protection against Omicron and other variants,” CDC Director Dr. Rochelle Walensky said in a press release.

Thursday’s authorization applies to any 16- or 17-year-old whose second shot took place six months ago. Santa Clara County residents can book a booster appointment at sccfreevax.org.