An advisory panel to the US Food and Drug Administration has recommended using the same strain composition for initial COVID-19 vaccines and boosters.

The panel of independent experts unanimously voted in favor of the move at a meeting on Thursday.

Two types of vaccines are currently in use. One is monovalent and targets the original coronavirus, and the other is bivalent and targets both Omicron variants and earlier strains. The type of vaccine given depends on whether it is a primary vaccination -- the first two shots -- or a booster.

Experts said simplifying vaccines will help get more people inoculated.

The panel also discussed the vaccination schedule and the need for periodic updates of COVID vaccines.

A proposed new schedule is one shot a year for the general population and two per year for young children and elderly people. The FDA also plans to conduct an assessment at least once a year to select which COVID strain vaccine to develop.

The panel did not reach conclusions on these subjects. One expert said more data is needed, particularly for young children. Another said there is a general agreement on updating the vaccine composition, but more information is needed to decide on the number of shots per year.