LONDON — Britain’s chief medical officers say children aged 12 to 15 should be vaccinated against coronavirus, despite a ruling by the government’s vaccine advisors that the step would have only marginal health benefits.

England Chief Medical Officer Chris Whitty and his counterparts in Scotland, Wales and Northern Ireland, said Monday that the children should be given a single dose of the Pfizer/BioNTech vaccine. They have yet to decide on a second dose.

The government has said it will follow the medical officers’ recommendations. Expanded vaccinations are expected to be part of a “tool kit” for dealing with the coronavirus in the fall and winter that Prime Minister Boris Johnson is due to announce on Tuesday.

Earlier this month Britain’s Joint Committee on Vaccination and Immunization said the vaccine should be given to 12- to 15-year-olds with underlying health conditions. But it did not back a rollout to healthy children in that age group, saying the balance of benefit and risk was unclear.

However, it said there might be wider societal factors to consider, such as on education or children acting as sources of transmission.

Countries including the United States, Canada, France and Italy already offer coronavirus vaccines to people aged 12 and up