The U.S. drug regulator granted full approval to the Pfizer Inc(PFE.N)/BioNTech SE COVID-19 vaccine - the first to secure such Food and Drug Administration validation.

Pfizer"s vaccine, which is administered in two doses 3 weeks apart, will still be under an EUA for recipients ages 12 to 15, and for immunocompromised individuals who qualify for a third dose of the vaccine 28 days after their second dose.

The FDA said it reviewed hundreds of pages of clinical study results and drug trial documentation before the approval, including details of a trial of 20,000 vaccine and 20,000 placebo recipients ages 16 and older who did not have evidence of the COVID-19 virus infection within a week of receiving the second dose. The FDA said 12,000 vaccine recipients have been followed-up for at least 6 months.