People infected with the Omicron coronavirus variant are much less likely to be admitted to hospital than those with Delta, the English public health authority said on Thursday, as the United Kingdom reported a record 119,000 cases of Covid-19.
Estimates by the British Health Security Agency showed that people with Omicron are between 50 and 70 percent less likely to need a hospital stay.
The UKHSA also found that people who received an additional coronavirus vaccine more than 10 weeks ago faced the first signs of weakened immunity against symptomatic Omicron infection.
Findings on lower virulence of Omicron compared to Delta are consistent with separate studies from Imperial College London and the University of Edinburgh published on Wednesday, with health data from South Africa, where a new variant was first identified. The growing body of evidence suggests that Omicron is less serious than Delta.
Sajid Javid, the British Minister of Health, said that the findings of the UKHSA were “promising”, but warned that the number of Omicron cases was increasing “at an extraordinary speed”. “Hospital admissions are increasing and we can’t risk the NHS being overloaded,” he added.
But Boris Johnson’s cabinet is at a standstill over whether new Covid restrictions should be imposed in England after Christmas.
The prime minister has promised to recall parliament if new regulations are introduced, which would lead to another conflict with his main bench and further rebellion by conservative lawmakers.
On Thursday, The UK recorded 119,789 cases of Covid-19 in the most recent 24-hour period, a new record daily figure for the pandemic, highlighting the rapid spread of Omicron across the country.
Government scientific advisers said that even if Omicron is less serious than Delta, the NHS could still be overloaded.
“A big wave of hospitalizations would likely follow a big wave of infections, even if there was a reduction in intrinsic weight,” the minutes of a meeting of the government’s Scientific Scientific Advisory Group on Emergencies said on Thursday.
Scientific advisers said Omicron’s intrinsic severity should fall “about 90 percent” compared to Delta’s hospital admissions “so it doesn’t reach previous peaks.”
The latest UKHSA analysis on Omicron was based on 132 people infected with the variant who sought hospital treatment in England by 20 December, adjusting to factors including age, underlying health conditions and vaccination status.
The Public Health Authority found that people infected with Omicron were 31 to 45 percent less likely to go to a hospital accident and ambulance compared to those with Delta.
Government officials said the reduction in the severity of Omicron stems from a combination of penetrating infections in vaccinated people and re-infections caused by a milder variant and potential changes in the biology of the virus.
UKHSA said its findings were “preliminary” and affected by “the small number of Omicron cases currently in the hospital, the inability to effectively measure all previous infections and the limited spread of Omicron to older age groups”.
A separate UKHSA analysis found that people who initially received Oxford / AstraZeneca and later received an additional mRNA injection saw that their protection against symptomatic Omicron infection dropped from 60 percent after two to four weeks to between 35 and 45 percent 10 weeks after the third dose.
For people who received three injections of BioNTech / Pfizer, the effectiveness of the vaccine dropped from 70 percent to about 45 percent after 10 weeks. For those who received two Pfizer stings, followed by a third dose of Moderna, the vaccine’s effectiveness remained between 70 and 75 percent after 10 weeks.
Government vaccine advisers are currently considering a case for recommending a fourth dose to compensate for the weakened immunity.
But the decisions of the Joint Committee on Vaccination and Immunization depend on data on the effectiveness of vaccines against serious diseases.
In London, where Omicron has spread the fastest in the UK, the number of people being treated in hospital primarily for severe Covid-19 has risen 25 per cent in the past week, to 1,197 patients with Covid since 19 December.
Matthew Taylor, executive director of the NHS Confederation, which represents organizations across the health sector, said the health service is facing a “double emergency” as “hospitalization increases” and “rapidly growing” staff must be isolated because of Omicron .