GENEVA – The Omicron coronavirus variant, reported in more than 60 countries, poses a “very high” risk globally, with some evidence it evades vaccine protection but clinical data on Its severity is limited, the World Health Organization said.
There are significant uncertainties around Omicron, which was first detected last month in southern Africa and Hong Kong, the WHO said in a technical press conference released on Sunday.
“The overall risk associated with the new variant of interest to Omicron remains very high for a number of reasons,” it said, reiterating its initial assessment on Nov.
On Monday, British Prime Minister Boris Johnson said at least one patient had died in the UK after contracting the Omicron variant.
The World Health Organization says there are early indications that vaccinated and previously infected people will not make enough antibodies to stop the infection from Omicron, leading to higher rates of transmission. high and “serious consequences”.
The WHO says it remains unclear whether Omicron is more contagious than the globally dominant Delta variant.
Supporting the WHO assessment, Oxford University researchers published a laboratory analysis on Monday that showed a significant decrease in the neutralization of antibodies against Omicron in people who have had Get two doses of the COVID-19 vaccine.
Although the antibody protection from the vaccines AstraZeneca and BioNTech/Pfizer has been destroyed, there is hope that T cells, the second pillar of the immune response, can prevent severe illness by way to attack infected human cells.
Some vaccine recipients did not produce any measurable neutralizing antibodies against Omicron, the Oxford researchers say. One of them, Matthew Snape, said it’s not yet clear how dramatic the real-world decline in vaccine effectiveness would be.
“We don’t know how much neutralizing antibodies are enough. We haven’t really determined what the threshold of protection is,” said Snape, adding that the best advice for unvaccinated people is to seek a course of treatment. primary and for those already vaccinated for a booster shot.
The Oxford researchers say there is no evidence yet that Omicrons cause more severe disease.
Their findings are fully consistent with another laboratory analysis last week of the blood of twice vaccinated people conducted by researchers at the Medical University of Innsbruck, Austria.
The analysis also noted a significant drop in Omicron-reactive antibodies, with many blood samples showing no reaction at all.
Both the Innsbruck and Oxford team said they would extend their study to people who had already received three doses of the vaccine.
Pfizer and BioNTech said last week that two shots of their vaccine could still protect against severe disease, because its mutations are not capable of evading the T-cell response.
They also said the third booster shot restored a level of antibody protection against Omicron comparable to that provided by the two-shot regimen against the virus originally identified in China.
WHO cited preliminary evidence that the number of people being reinfected with the virus had increased in South Africa.
While early findings suggest that Omicron may be less severe than the Delta variant, more data is needed to determine if Omicron is less dangerous.
“Even if the severity may be lower than that of the Delta variant, it is expected that the number of hospitalizations will increase due to increased transmission. More hospitalizations could put a strain on the health system. and lead to more deaths,” it said.
More information is expected in the coming weeks, it added, noting the time interval between infections and results.
(Reporting by Stephanie Nebehay in Geneva, Ludwig Burger in Frankfurt, Editing by William Maclean, Robert Birsel and Barbara Lewis)