The coronavirus vaccine may not grant full immunity after just one dose, according to a new report.

When a vaccine proves effective, there’s a good chance it will entail a two-dose series, USA Today reported. Shots may need to be administered one month apart, with a booster following several years later.

As of June 2, the World Health Organization (WHO) listed 10 vaccine candidates under clinical evaluation, with 123 candidates in preclinical evaluation.

Barry Bloom, immunologist and professor of public health at the Harvard T.H. Chan School of Public Health in Boston, told USA Today that almost all of the vaccine developers are considering two shots in their regimens.

According to the outlet’s report, the first shot in the series would “prime the immune system” to help the body recognize the virus, followed by a second shot to “strengthen the immune response.”

When vaccine candidates reach human clinical trials, more precise dosing will become clear, Dr. Kelly Moore, associate director of immunization education for the Immunization Action Coalition, told the outlet.

After the first dose of a vaccine, the immune system develops antibodies and immune cells in about 14 days, says L.J. Tan, chief strategy officer with the Immunization Action Coalition and co-chair of the National Adult Immunization Summit and National Influenza Vaccine Summit.

Tan estimated any COVID-19 vaccine requiring two doses would likely be administered about a month or two apart. FOX News