Enlarge / A health worker administers a third dose of the Pfizer-BioNTech COVID-19 vaccine to an elderly resident at Ichilov medical center in Tel Aviv, Israel, on Monday, Aug. 2, 2021. (credit: Getty | Bloomberg)

The US Food and Drug Administration on Tuesday announced the authorization of second booster doses of both the Pfizer/BioNTech and Moderna COVID-19 vaccines for people ages 50 and above, as well as certain immunocompromised people.

The FDA’s decision, which was made without consulting its panel of independent expert advisers, was expected this week.

“Current evidence suggests some waning of protection over time against serious outcomes from COVID-19 in older and immunocompromised individuals,” Peter Marks, the FDA’s top vaccine regulator, said in a statement. “Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals.”