LONDON (AP) — Britain's government extended its COVID-19 booster programs to younger people Monday, hoping to stave off a fresh wave of infections during the colder winter months.

The Joint Committee on Vaccination and Immunization said people aged 40 to 49 will also be eligible for a vaccine booster shot six months after their initial shot. People 50 and over had previously been eligible.

The decision comes after a senior U.K. official told Sky News that the vaccination program offered the best opportunity to prevent a re-imposition of restrictions over Christmas.

“It is in our hands,'' Conservative Party chairman Oliver Dowden said. “If you get the booster when the call comes, that is the biggest wall of defense that we have against COVID.”