In a major policy shift, federal health officials anticipate the shots will be made available to adults 65 and older as well as children and younger adults who have one or more risk factors that make them more vulnerable to severe COVID-19.

Large, lengthy studies will be needed for the agency to approve boosters for healthy adults and children, regulators said.

Nuvaxovid had been available under emergency use authorization but the full approval may allow it to better compete with rival vaccine makers.