LONDON (BLOOMBERG) - Prime Minister Boris Johnson's government said every adult in England has had the chance to receive a Covid-19 vaccine booster, the critical part of its strategy for tackling the fast-spreading omicron variant.

More than 28.1 million people in England have now had their top-up doses, the Department of Health said in a statement on Friday, or about seven of 10 eligible adults.

The UK's other devolved constituent nations make their own health policy.

Mr Johnson has repeatedly pointed to the vaccine roll-out as the rationale for not imposing tougher pandemic restrictions to slow the tide of Omicron cases.

"It's precisely because of that huge national effort that we can celebrate tonight at all," Mr Johnson said in his New Year's message.

But his strategy to get through the latest virus wave with an accelerated inoculation programme combined with home testing is coming under growing pressure amid a widespread shortage of testing kits and as the soaring caseload starts to test the resilience of the health service.

A total of 11,452 people were in the hospital in England with Covid-19 as of Thursday (Dec 30), according to the latest NHS England figures, far short of the peak of more than 34,000 in January.

Still, daily admissions are also rising, with 2,082 on Tuesday - the most since Feb 3.

'War footing'

The National Health Service is "on a war footing", Dr Stephen Powis, its national medical director, said in a statement on Thursday announcing the construction of temporary structures at eight hospitals to care for more patients.

The move, described as precautionary, is reminiscent of the so-called Nightingale hospitals set up during the first Covid-19 wave in 2020 that were later closed because they were little-used.

There is growing evidence that Omicron is causing less serious disease than earlier coronavirus variants, including the previously dominant Delta.

Yet some scientists are worried that the sheer number of Covid-19 cases could strain the NHS, even if the proportion of people needing treatment is smaller.

Mr Johnson has said about 90 per cent of people hospitalised with Covid-19 haven't had vaccine boosters, and on Friday he urged holdouts to come forward.

Booster drive

"I want to speak directly to all those who have yet to get fully vaccinated," he said. "The people who think the disease can't hurt them - look at the people going into hospital now, that could be you."

The UK recorded 189,213 confirmed Covid cases on Thursday, breaking the daily case record for a second day, fuelled by the spread of Omicron.

A further 332 more deaths within 28 days of a positive coronavirus test were also recorded, the highest daily total since March, though NHS England said that includes a "backlog" of fatalities not reported over the holiday period.

That is also piling pressure on the other plank of Mr Johnson's Covid strategy: encouraging people to use home testing kits to avoid spreading the virus.

With demand surging, they have been repeatedly unavailable to order on the NHS website, while pharmacies have complained of "inconsistent" supplies.

Under new pandemic rules in England, people can use the tests to end their self-isolation, increasing demand.

Businesses have started to voice concern about the impact on supply chains due to staff absences, which are also increasingly serious in the health service.

On Thursday, Southern Railway announced it is suspending services to the busy London Victoria station until Jan 10 because so many employees are isolating due to the coronavirus.