As of Dec. 21, about 73 per cent of new Covid-19 cases that have been sequenced in the United States were from the Omicron variant, Bloomberg reported.
As late as November, 99.5 per cent of Covid-19 infections in the U.S. were caused by the Delta variant, Associated Press (AP) reported.
Now, the Delta variant only accounts for 27 per cent of the sequenced Covid-19 cases in the U.S.
This makes the Omicron variant the dominant strand of Covid-19 in the U.S., AP noted.
Six-fold increase of Omicron in a week
The U.S. Centres for Disease Control (CDC) said that within a week, they had recorded a six-fold increase of Omicron cases in the country, AP reported.
Due to its increased transmissibility, authorities fear that the wave of infection due to the Omicron variant will strain the country's healthcare system.
The CDC added that they are expecting the rise in Omicron cases in the states as the pattern is similarly seen in other parts of the world, Bloomberg reported.
Furthermore, the CDC said that in some parts of the U.S., such as New York, New Jersey, and Washington, more than 90 per cent of the Covid-19 cases were caused by the Omicron variant.
"Unwise" to say Omicron is milder
According to the World Health Organisation's (WHO) chief scientist, Soumya Swaminathan, it is "unwise" to say that the Omicron strain is milder as compared to other Covid-19 variants, Reuters reported.
She added that Omicron also successfully evades some immune responses.
She recommended that booster shot programmes ought to be targeted to people with weaker immune systems, Reuters reported.
The director-general of WHO, Tedros Adhanom Ghebreyesus, said that there is consistent evidence that Omicron is spreading significantly faster than the Delta variant, and that it is more likely for individuals who had been vaccinated against Covid-19, or those who had recovered from Covid-19, to be infected or reinfected.
Both their comments were similar to a study done by Imperial College London, which showed that the risk of reinfection by the Omicron variant was five times higher than Delta.
WHO urged to postpone gatherings
Tedros added that the year-end holidays would lead to an increase in the number of Covid-19 cases, overwhelming the healthcare system and rising death toll, Reuters reported.
He also urged people to postpone gatherings over the holidays.
"An event cancelled is better than a life cancelled," he said.
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