https://www.siliconvalley.com/2021/12/09/fda-expands-booster-authorization-to-teens-16-years-and-up/

Just weeks after granting emergency use authorization for Pfizer’s COVID-19 vaccine to adults 18 and older, the U.S. Food and Drug Administration expanded it Thursday to teens 16 and 17 years old, citing concerns about rising cases, a mutating virus and new information indicating the benefits outweigh the risks.

“As people gather indoors with family and friends for the holidays, we can’t let up on all the preventive public health measures that we have been taking during the pandemic,” said Acting FDA Commissioner Dr. Janet Woodcock. “With both the delta and omicron variants continuing to spread, vaccination remains the best protection against COVID-19.”