Boris Johnson’s government was mulling the idea of giving a fourth Covid vaccination to vulnerable people in line with Israel’s example but has just been advised by its own health experts that this is currently not necessary.

On Friday night, the Joint Committee on Vaccination and Immunisation (JCVI) announced that booster jabs — that is a third dose after the initial two — continue to provide high levels of protection against severe disease from omicron in older adults, including the most vulnerable.

Prof. Wei Shen Lim, the JCVI’s chairman of Covid immunisation, said: “The current data show the booster dose is continuing to provide high levels of protection against severe disease, even for the most vulnerable older age groups.

“For this reason, the committee has concluded there is no immediate need to introduce a second booster dose, though this will continue to be reviewed.”

Andrew Pollard, the chairman of the JCVI, added that “more strong evidence is needed” before the rollout of a fourth vaccine.

“We can’t vaccinate the planet every four to six months. It’s not sustainable or affordable. In the future, we need to target the vulnerable.”

The UK has reported a further 178,250 Covid cases as the omicron variant continues to fuel a wave of infections.

The latest figures, which reflect infections picked up by testing, bring the UK total for the past seven days to 1,260,535, up 20 per cent compared with the total for the week before. However, the daily figure is lower than those recorded in recent days, with 179,756 cases reported on Thursday and 194,747 on Wednesday.

The true number of infections is estimated to be substantially higher as not all infections are captured by the testing programme.

Speaking during a visit to King’s College Hospital in south London, Sajid Javid, the health secretary, said: “When we look at omicron versus the previous variants, of course there are some encouraging signs. We know now that omicon is less severe.”

However, Javid emphasised the need for people to come forward for their booster jabs amid “challenging times” for the NHS.

The JCVI said rolling out a fourth jabs programme “would add to the significant existing operational pressures”, noting that “the current omicron wave is progressing very swiftly, offering limited time for additional vaccine programme measures to have a substantial impact within this wave”.

The committee said that, even among the most vulnerable, a fourth jab would provide “limited additional benefit against severe disease at this present time” and that the main aim of the vaccination programme remained prevention of severe disease, not protection against mild or asymptomatic infection.

Protecting against all infection would require regular jabs which “is not considered a sustainable long-term strategy”, the committee said.

It added that alternative vaccines including variant-specific jabs, which could become available later this year, may prove better suited to providing long-term protection against novel variants.