The rising wave of Omicron infections could lead to daily hospitalisations from Covid exceeding the peak of last winter, when more than 4,500 people in the UK were admitted on a single day, England’s chief medical officer has said. The staggering speed at which Omicron is spreading means large numbers of vulnerable people may need hospital care over a very short space of time, Prof Chris Whitty told MPs on Thursday, with daily admissions potentially peaking above that seen last winter at the start of the vaccine programme. On Thursday, the UK set another grim record for the Covid epidemic with 88,376 new cases reported, a 31.4% rise on the week. The number of confirmed Omicron cases rose to 11,708, up 1,691 on Wednesday. The latest figures from the UK Health Security Agency show the doubling rate for Omicron is less than two days in all regions of England apart from the south-west. Cases are doubling every one-and-a-half days in London where 73.5% of Covid cases are now expected to be Omicron. The highest number of Covid hospitalisations in a day in the UK was 4,583 on 12 January, when the Alpha variant – first spotted in Kent – was dominant. Omicron is now the dominant variant in London and is expected to become the most common in England within days or weeks. “Even if it is milder, because it is concentrated over a short period of time you could end up with a higher number than that going into hospital on a single day. That is entirely possible,” Whitty told the health and social care committee. “The whole point about this is it’s going to be really concentrated in a very short period of time, very possibly.” Dr Susan Hopkins, the chief medical adviser for the UK Health Security Agency, said the UK was experiencing two Covid epidemics, with cases of Delta largely flat and Omicron doubling every two days. She said the R number – the number of people an infected person typically passes the virus on to – for Omicron was estimated at between three and five. Whitty said many people failed to appreciate that the NHS was likely to face a sudden influx of Covid patients at a time when it would be struggling for staff because of infections and illness. The broader economy was also at risk as the variant swept across the country, he added. “The numbers in hospital over a short period could be very high indeed. This will be happening at a time when a very significant number of staff are going to be off ill, isolating or caring. So you’re going to have both a reduction in supply and an increase in demand in the health service over a very short time period, and that really is the reason why we’re all taking this extremely seriously,” Whitty said. “One risk that is going to happen irrespective is, because of the steepness of this, even if this ended up in a situation where boosters do hold this to a large degree for a lots of people … a lot of people will simultaneously fall ill and be unwell, isolating or caring for others at the same time across the whole economy.” Covid cases are rising most steeply among those aged 20-29, followed by people in their 30s, although children aged five to nine, and 10- 19-year-olds still have the highest rates of infection, according to the UKHSA’s Covid surveillance report released on Thursday. On 12 December, 67.9% of the UK population had received at least one dose of vaccine and 62.2% had received two shots. More than 80% of the over-70s have received a booster. Some early reports from South Africa raised concerns that the Omicron variant might be slightly more severe than Delta in children, but Whitty said this was not being seen in the UK and the assumption was that it was still far more serious for older people than those who were young and healthy. Before the vaccination programme in the Alpha wave, more than a fifth of people over the age of 65 who caught Covid were hospitalised. This fell to 6% as the vaccine rollout protected the oldest and most vulnerable people. Whitty said at worst the UK may go back to the hospital admission rate seen in January, but a booster may protect more people against severe disease from Omicron than two shots did against severe disease caused by Delta. He urged people to get vaccinated or boosted as soon as they became eligible and emphasised that vaccine coverage among pregnant women was still “depressingly low”. Almost all pregnant women with Covid in hospital and intensive care are unvaccinated. “Significant numbers of women have come to serious harm as a result of this,” he said, blaming “myths” about vaccine safety in the group for the low uptake. “What is true is that Covid and pregnancy is a dangerous combination and we absolutely should be encouraging everybody who is pregnant to get vaccinated.” The most difficult decision now, Whitty said, was how to balance family visits to people in care homes with safety. “What we don’t want is a situation where over the Christmas period people are left completely alone, but nor do we want to have outbreaks we can avoid. We’re trying to navigate a route between those two very clear needs. That is probably the most difficult decision at this point,” he said. Early estimates from South Africa have suggested that Omicron may cause milder disease than previous waves of Covid. That would be expected, since people catching Omicron, which was discovered only last month, have more immunity to Covid because of previous infection or vaccination. Hopkins said the UKHSA would be able to assess Omicron severity and vaccine protection in Britain once about 250 people had been hospitalised with the variant. “The earliest we will have reliable data is the week between Christmas and New Year, and probably early January,” she told MPs.