SAN FRANCISCO (KRON) — Phase 3 trial results by biotech company Regeneron showed its new drug provides long-term protection against COVID-19.

A single dose of the antibody cocktail reduced the risk of contracting COVID-19 by 81.6% during months 2-8, according to results released Monday. Previously published results already showed its effectiveness within one month of getting the injection.

Regeneron said none of the participants who were injected with a single dose of the “REGEN-COV” antibody cocktail were hospitalized with COVID-19 during the eight-month trial run in collaboration with the National Institute of Allergy and Infectious Diseases.

Meanwhile, six people in the placebo group were hospitalized with COVID-19, the results revealed.

“These results demonstrate that REGEN-COV has the potential to provide long-lasting immunity from SARS-CoV-2 infection, a result particularly important to those who do not respond to COVID-19 vaccines including people who are immunocompromised,” said Myron S. Cohen, M.D., who leads the monoclonal antibody efforts for the NIH-sponsored COVID Prevention Network.

Participants in both the placebo group and the test group were allowed to get the COVID-19 vaccine after the first month, Regeneron said, but the number of people vaccinated was balanced: 34.5% of the REGEN-COV group and 35.2% of the placebo group received at least one COVID-19 vaccine dose by the end of the eight-month trial.

Regeneron said its drug is not authorized as a substitute for the vaccine, however.

REGEN-COV currently has emergency use authorization in the U.S. to treat people who already have mild to moderate COVID-19 symptoms and are at high risk of more serious consequences from the COVID-19 infection. It’s not authorized for people who are already hospitalized with COVID-19, according to the company.

The Food and Drug Administration has agreed to review applications for the antibody cocktail and is expected to take action in April 2022.