CNN  — 

Pfizer and BioNTech said on Tuesday they’re seeking emergency use authorization from the US Food and Drug Administration for a Covid-19 vaccine booster for all individuals age 18 and older. The companies are seeking an amendment to the existing EUA for booster doses for some adults.

The companies said the submission is based on results of a Phase 3 trial involving more than 10,000 participants; it found boosters were safe and had an efficacy of 95% against symptomatic Covid-19 compared with the two-dose vaccine schedule in the period when the highly transmissible Delta was the dominant strain. Pfizer released the booster efficacy data last month; it has not yet been peer-reviewed or published.

Authorization would bring the country one step closer to President Joe Biden’s mid-August prediction that boosters would be available for all adults in the United States. When Pfizer initially sought the FDA’s OK for booster doses, it applied for full approval of boosters for everyone age 16 and older. Instead, the FDA authorized boosters for a more limited group of adults once they were far enough past their initial vaccine doses.

Since then, eligibility has expanded to include the majority of adults, including people who received other types of vaccines. People who got the Pfizer/BioNTech or Moderna Covid-19 vaccines six months ago or longer may get a booster if they are 65 or older; at risk of severe Covid-19 from a breakthrough infection because of a medical condition such as diabetes, kidney disease or pregnancy; or at risk because of living conditions or work. Anyone who got the Johnson & Johnson shot two months ago or longer is eligible two months after getting their first shot. The J&J vaccine is only authorized for people age 18 and older. The FDA and CDC also signed off on mixing and matching boosters.

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The new request from Pfizer and BioNTech comes as federal health officials have made clear their concern about waning immunity as the nation heads into the winter months.

The Pfizer/BioNTech vaccine is already authorized for use in people from ages 5 to 15, and approved for people age 16 and older.