The omicron variant of the coronavirus has been detected in 89 countries, and COVID-19 cases involving the variant are doubling every 1.5 to 3 days in places with community transmission and not just infections acquired abroad, the World Health Organization said Saturday.
The variant, first discovered in late November, has been spreading rapidly even in countries with high vaccination rates or where a significant proportion of the population has recovered from the disease, but it is not yet clear if Omicron’s rate of transmission was because it was less prone to immune responses, higher transmissibility, or a combination of both, the WHO said.
“There are still limited data on the clinical severity of Omicron. More data are needed to understand the severity profile and how severity is impacted by vaccination and pre-existing immunity,” the organization said.
“There are still limited available data, and no peer-reviewed evidence, on vaccine efficacy or effectiveness to date for Omicron,” it added.
But Omicron’s “substantial growth advantage” over the Delta variant means it is likely to soon overtake Delta as the dominant form of the virus in countries where the new variant is spreading locally, the UN health agency said.
South Africa reported Omicron to the WHO on November 24, prompting countries around the world to impose travel bans and reintroduce domestic restrictions to slow its spread.
The WHO said earlier this week that Omicron was more transmissible than the Delta strain and reduces vaccine efficacy but causes less severe symptoms, according to early data.
Faster transmission was noted in South Africa, where Delta is less prevalent, and in Britain, where Delta is the dominant strain.
Dr. Mike Ryan, the executive director of the WHO Health Emergencies Program, said Friday that “we have had “two years of serial transmission in millions and millions of human beings, so the virus has had two years to really become much better adapted to entering human cells.”
The Omicron variant has “a change in its genetic sequence that has changed the shape…and the ability of the spike protein to attach to human cells…And that is probably what is giving it its transmission advantage,” said Ryan, adding that there are still many unknowns such as the survivability of virus variant on surfaces.
In Israel, the latest Health Ministry coronavirus figures released Friday showed 838 new COVID-19 cases diagnosed the previous day, the highest daily figure in some two months.
The number represented an increase of 181 from the previous day, as the pandemic appeared to be on an upward trajectory in Israel once more amid concerns over the spread of the Omicron variant.
The latest numbers also showed Israel’s basic virus reproduction rate had risen to 1.07. Also known as the “R-number,” the figure represents the number of people each confirmed patient infects, on average. Any number over 1 signifies that case numbers are rising.
The Omicron coronavirus strain has dominated policy talks, leading Israel to once again shutter its borders to most foreigners and impose fresh restrictions on Israelis returning from countries with high infection rates.
The ministry said 45 of the new cases had been confirmed to be of the Omicron variant, bringing the total number of Omicron cases in Israel to 134. Most of the cases were found in people returning from overseas. There were an additional 207 likely cases waiting to be confirmed.
The ministry added that 92 of the 134 cases were in people who were considered “protected” with either a booster shot, two doses in the last six months or recently recovered. It did not say how severe their cases were.
The threat of a rapid spread of the new strain has also led the government to briefly announce the implementation of the Green Pass system at malls starting Friday (requiring proof of immunity or a negative test to access non-essential shops). But a public outcry from business owners and threats of rebellion has led the plan to be shelved for now.
It is not clear that the rise in infections in Israel has been caused by Omicron, but the highly mutated strain is growing in presence in the country.
On Friday, opposition leader Benjamin Netanyahu and some 130 others at the Knesset entered quarantine, after four parliamentary personnel were confirmed to be carriers of coronavirus, officials said.
According to Hebrew-language media reports, at least one is suspected to be a carrier of the Omicron variant of COVID-19.
There is also growing concern about the spread of coronavirus among students. On Thursday, an all-girls religious school in Jerusalem was closed temporarily and went to remote learning after at least 62 COVID cases were reported there (though it was not yet clear whether the cases were of Omicron).