While a vaccination campaign is being rolled out in the United States using approved emergency vaccines for COVID-19, another possible vaccine is undergoing clinical trials, Voice of America reported.

Vaccines from Pfizer-BioNTech and Moderna are distributed according to strict rules, and the availability of additional options is essential to ensure sufficient doses are available domestically and globally.

Novavax is recruiting 30,000 volunteers to test its vaccine, which differs from the first two.

Other vaccines are on the way.

For example, Johnson & Johnson hopes to find out in January if its one-injection vaccine works.

Meanwhile, the UK is considering giving the green light to the AstraZeneca vaccine.