The data was from two studies — a late-stage study evaluating the booster in adults and adolescents who had received Novavax primary vaccination and another study testing it in those aged 18 to 49 who had received primary series of Novavax vaccine or other authorized or approved vaccines.

In the late-stage study, a single homologous booster dose significantly increased antibody levels against these variants relative to pre-boost levels, the company said.

"These data are an early indication that our vaccine may be effective against variants such as Omicron," Novavax executive Gregory M. Glenn said.

The company said ongoing trials are studying the efficacy of the vaccine against variants including BA.4 and BA.5.