A healthcare worker prepares the administration of the COVID-19 vaccine at Long Island Jewish Medical Center in New York, the United States, on Dec. 14, 2020. (Photo: Xinhua)

The Phase 3 trial of another investigational COVID-19 vaccine has begun enrolling adult volunteers, the U.S. National Institutes of Health (NIH) announced on Monday.

The randomized, placebo-controlled trial will enroll approximately 30,000 people at approximately 115 sites in the United States and Mexico.

It will evaluate the safety and efficacy of NVX-CoV2373, a vaccine candidate developed by biotechnology company Novavax, Inc.

Volunteers will be asked to give informed consent prior to their participation in the trial. They will be grouped into two cohorts: individuals 18 through 64 years old and those aged 65 and older, with a goal of enrolling at least 25 percent of all volunteers who are 65 years old or older.

Participants will be followed closely for potential vaccine side effects and will be asked to provide blood samples at specified time points after each injection and during the following two years, according to the NIH.

Scientists will analyze the blood samples to detect and quantify immune responses to SARS-CoV-2, the virus that causes COVID-19.

Novavax is leading the trial as the regulatory sponsor. The U.S. National Institute of Allergy and Infectious Diseases, and the U.S. Biomedical Advanced Research and Development Authority, are funding the trial.