Britain’s health authorities said on Sunday that bookings for the Covid booster vaccines for everyone aged 30 and over in England would be open from Monday, as one of the key actions aimed at tackling the rapid spread of the omicron variant of the coronavirus in the country.

There are around 7.5 million people aged 30-39, and 3.5 million of those are eligible for boosters from Monday, NHS England said. It comes as early analysis shows booster jabs being effective against the omicron variant, the first cases of which have started being hospitalised now.

There is no reported death from the variant in the UK yet, but experts warn that it is set to take over from delta as the dominant coronavirus variant by the end of this year.

“The Covid-19 booster programme is accelerating rapidly and more than 22 million people in the UK have already received their top-up, securing vital protection ahead of Christmas,” said UK health secretary Sajid Javid.

“This is our national mission — the most recent data shows boosters are the essential defence against omicron and we are doing everything in our power to get jabs into arms as quickly as possible. We are now expanding the offer to over-30s — so please come forward to get boosted and help our country get ahead in this race with the variant,” he said.

The expansion of the booster programme follows updated advice from the Joint Committee on Vaccination and Immunisation (JCVI), allowing millions more people to book their third top-up dose. The booking can be made two months on from their second dose, which is a month in advance of becoming eligible to receive the jab — a gap set at three months from the second dose by the JCVI.