The 'super mutant? Omicron strain is 4.2 times more transmissible in its early stages than the Delta variant of the coronavirus, a new Japanese study has found.
Since the Omicron strain, which has a record number of mutations, was discovered in South Africa last month, the World Health Organization (WHO) and medical scientists around the globe have been expressing concerns that it could turn out to be more contagious and more resistible to the current vaccines.
The new research, which was presented at a meeting of Japan's health ministry's advisory panel on Wednesday, appears to be another confirmation of those fears.
"The omicron variant transmits more, and escapes immunity built naturally and through vaccines more," Hiroshi Nishiura, a professor of health and environmental sciences at Kyoto University, said during the meeting.
Nishiura, who specializes in mathematical modeling of infectious diseases, had analyzed data that came from South Africa's Gauteng province as of November 26.
His model has shown that in the early phase of the Omicron outbreak the effective reproduction number - the average number of people who got infected from a single carrier - surpassed the R-number of the Delta variant by 4.2 times.
The number of cases in South Africa has been relatively low in recent months, but it jumped to almost 20,000 cases a day after the Omicron variant emerged. However, observations by the WHO have suggested that the mutated strain didn't make the disease harsher, with the majority of its receded cases being mild or moderate.
Nishiura's study hasn't yet been peer-reviewed and published in a scientific journal. But its findings were enough for the head of the advisory board Takaji Wakita to suggest that Japanese health authorities "need to get prepared for a domestic Omicron outbreak."
Vaccine makers have already rushed to update their jabs so that they can effectively tackle the new variant. Pfizer said it plans to present its Omicron-specific candidate to the US regulator in March. Moderna expects to have an updated vaccine within 60 to 90 days.