Pfizer and BioNTech announced Thursday that a large-scale trial of their coronavirus disease 2019 (Covid-19) vaccine booster showed it restored full protection against the disease.

In Phase 3 randomized, controlled trial, a Pfizer-BioNTech booster dose was administered to more than 10,000 individuals 16 years of age and older, who previously received the Pfizer-BioNTech primary two-dose series.

It showed relative vaccine efficacy of 95.6 percent when compared to those who did not receive a booster.

These are the first efficacy results from any randomized, controlled Covid-19 vaccine booster trial.

“These results provide further evidence of the benefits of boosters as we aim to keep people well-protected against this disease,” said Albert Bourla, Pfizer chairman and chief executive officer.

Last month, the U.S. Food and Drug Administration authorized the booster shots for the Pfizer-BioNTech Covid-19 vaccine, allowing a single booster dose of it to be administered at least 6 months after completion of the primary series to individuals 65 years of age and older, and 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2. (PNA)