Moderna asks FDA to approve fourth COVID-19 vaccine shot

March 18 (UPI) -- Moderna said on Thursday it has approached the Food and Drug Administration to authorize a second COVID-19 booster shot for everyone 18 and older to address the waning effectiveness of its previous three shots against the virus and its variants.

The announcement comes after Pfizer and BioNTech, makers of the other widely used coronavirus vaccine in the United States, submitted a request for approval of another booster shot for adults 65 and older.

"This submission is based in part on recently published data generated in the United States and Israel following the emergence of Omicron [variant]," Moderna said in a statement. "Moderna continues to collect and monitor real-world data on its COVID-19 vaccine.

"Real-world evidence continues to confirm the effectiveness and robust safety profile of the Moderna COVID-19 vaccine. Clinical trials are ongoing for Moderna's Omicron-specific booster and a bivalent Omicron-specific booster."

An Israeli study released Wednesday in the New England Journal of Medicine found that a fourth dose of the Pfizer/BioNTech and Moderna COVID-19 vaccines was safe and boosted antibody levels similar to what was seen after a third dose.

"Along with previous data showing the superiority of a third dose to a second dose, our results suggest that maximal immunogenicity of mRNA vaccines is achieved after three doses and that antibody levels can be restored by a fourth dose," the Israeli study said.

While some countries are already offering the fourth shot, it is currently only available in the United States for certain people with weakened immune systems.