FDA authorizes second COVID-19 booster for people 50 and older

The Food and Drug Administration on Tuesday authorized a second booster shot of the Pfizer and Moderna coronavirus vaccines for individuals aged 50 and older.

The shots are designed to work as short-term immunity boosters as the novel virus continues to morph into new and more contagious variants. The shot is also intended to protect against severe illness. 

Providers will be given the go-ahead to begin administering the fourth shot once Centers for Disease Control and Prevention Director Rochelle Walensky signs off on the measure.

Immunocompromised people are already eligible for the fourth shot.

"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," said Peter Marks, director of the FDA's Center for Biologics Evaluation and Research.

"Additionally, the data show that an initial booster dose is critical in helping to protect all adults from the potentially severe outcomes of COVID-19. So, those who have not received their initial booster dose are strongly encouraged to do so."

It is unclear how long protection from a second booster shot will last.