Findings by UK Health Security Agency add to emerging evidence that Omicron produces milder illness than other COVID variants.
Preliminary data suggest that people with Omicron variant of coronavirus are between 50 percent and 70 percent less likely to need hospitalisation than those with the Delta strain, The United Kingdom’s public health agency has said.
The UK Health Security Agency’s findings, published on Thursday, add to emerging evidence that Omicron produces milder illness than other variants – but also spreads faster and better evades vaccines.
The agency said that based on cases in the UK, an individual with Omicron is estimated to be between 31-45 percent less likely to attend a hospital emergency department compared with one with Delta “and 50 to 70 percent less likely to be admitted to hospital”.
It cautioned that the analysis is “preliminary and highly uncertain” because of the small number of Omicron patients in hospitals and the fact that most were in younger age groups.
As of December 20, 132 people had been admitted to UK hospitals with confirmed Omicron, of whom 14 – aged between 52 and 96 – died.
Scientists caution that any reductions in severity need to be weighed against the fact that Omicron spreads much faster than Delta and is more able to evade vaccines.
The agency’s research said the protection a booster shot of vaccine gives against symptomatic Omicron infection appears to wane after about 10 weeks, though protection against hospitalisation and severe disease is likely to hold up for longer.
UKHSA chief executive Jenny Harries said the analysis “shows an encouraging early signal that people who contract the Omicron variant may be at a relatively lower risk of hospitalisation than those who contract other variants”.
But she added that “cases are currently very high in the UK, and even a relatively low proportion requiring hospitalisation could result in a significant number of people becoming seriously ill”.
UK Health Secretary Sajid Javid said the emerging information about Omicron was “encouraging news,” But he said it was “not very clear yet … by how much that risk is reduced” compared with Delta.
The analysis follows two studies, from Imperial College London and Scottish researchers, that found patients with Omicron were between 20 percent and 68 percent less likely to require hospital treatment than those with Delta.
Data out of South Africa, where the variant was first detected, have also suggested Omicron might be milder there.
But even if the early studies are borne out, the new variant could still overwhelm health systems because of the sheer number of infections.
The British health agency said Omicron appeared able to re-infect people more easily than previous variants, with 9.5 percent of Omicron cases found in people who had already had COVID-19 – a figure it said was likely an underestimate.
Countries around the world are looking closely at the UK, where Omicron is now dominant and where COVID-19 cases have surged by more than 50 percent in a week.
The UK reported 119,789 lab-confirmed COVID-19 cases on Thursday, the highest yet during the pandemic and the second day the number has topped 100,000.
The Office for National Statistics estimated that about one in 45 people in private households in England – 1.2 million individuals – had COVID-19 in the week to December 16, the highest level seen in the pandemic.
The UK government this month reinstated rules requiring face masks in shops and ordered people to show proof of vaccination or a negative coronavirus test before entering nightclubs and other crowded venues in an attempt to slow Omicron’s spread.
The government said on Thursday it would not impose any new restrictions before Christmas, but might do so soon after. It is hoping vaccine boosters will provide a bulwark against Omicron, as the data suggest, and has set a goal of offering everyone 18 and up a third shot by the end of December.