A government advertisement at a bus stop in London urges people to get booster shots against COVID-19 as the Omicron variant of the coronavirus spreads worldwide on December 28, 2021.
Vuk Valcic | SOPA Images | LightRocket | Getty Images
According to a large study published by the UK authorities on Friday, people infected with omicron are less likely to need inpatient treatment compared to patients who have had delta infection.
The latest data from the UK Health Safety Agency showed that the risk of hospitalization for people infected with omicron is about a third of the risk associated with the delta variant. The study analyzed over 528,000 omicron cases and 573,000 delta cases from 22 November to 26 December in England.
However, Chief Medical Adviser Susan Hopkins warned that it is too early to draw definitive conclusions about the seriousness of the omicron-related illness.
“The increased transmissibility of omicron and an increase in the number of cases among the population over 60 in England means that it remains highly likely that the NHS will be under significant pressure in the coming weeks,” Hopkins said, citing the UK’s National Health Service.
The World Health Organization also warned on Wednesday that it is too early to conclude that omicron is milder than previous Covid variants. Dr Abdi Mahamoud, WHO’s manager of Covid incidents, said omicron has so far infected mostly young people, who usually develop less serious illness.
“We all want this disease to be milder, but so far the affected population is younger. How it behaves among the elderly, vulnerable – we do not yet know, ”said Mahamud at a briefing in Geneva.
A new study in the UK also found that Covid vaccines reduced the risk of hospitalization due to omicron across the board, although the booster dose provides the highest level of protection. The latest data add to a growing body of evidence demonstrating that although vaccines have been affected by the omicron, they still offer a significant level of protection compared to unvaccinated people.
According to the study, one dose of the vaccine was 52% effective in preventing hospitalization due to the omicron variant, while two doses were 72% effective. However, after 25 weeks the effect of the two doses was weakened, and their effectiveness in preventing hospitalization was 52%.
Booster doses significantly increase protection and are 88% effective in preventing hospitalization two weeks after injection, the study said.
“Protection against hospitalization due to vaccines is good against the omicron variant,” the UK Health Safety Agency concluded in its report.
However, the agency found that existing vaccines were less effective at preventing symptomatic omicron infection than the delta option. AstraZeneca vaccine, approved in the UK but not in the US, does not provide protection against symptomatic omicron infection 20 weeks after the second dose.
Pfizer and Moderna vaccines, the most widely used vaccines in the United States, are only about 10% effective at preventing symptomatic omicron infection 20 weeks after the second dose. Booster doses, however, increase protection and are up to 75% effective in preventing infection two to four weeks after the third injection. However, boosters fade after about 10 weeks, providing 40-50% protection against symptomatic infection, the study says.
UK Health Minister Sajid Javid said unvaccinated people are eight times more likely to be hospitalized from Covid.