Omicron Subvariant 1.5 Times More Contagious Than Omicron

Carolyn Crist

January 31, 2022

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The Omicron subvariant, known as BA.2, spreads about 1.5 times faster than the original Omicron strain, known as BA.1, according to CNBC.

The Statens Serum Institut, which monitors infectious diseases in Denmark, said that BA,2 is more contagious, but it doesn't appear to increase hospitalizations or reduce how well the vaccine works.

BA.2 overtook BA.1 as the primary variant in Denmark within a few weeks, Troels Lillebaek, director of the institute, told CNBC. The subvariant has five unique mutations on a key part of the spike protein, which is what the coronavirus uses to invade human cells, he said. This often means a higher rate of spreading.

The Omicron subvariant has been detected in at least 29 states in the U.S. and 56 countries, according to the latest update from The U.S. has detected 188 infections, with the worldwide total nearing 25,000.

Denmark has reported the highest number of cases, followed by the United Kingdom and India. Both Denmark and India have reported that BA.2 now accounts for about half of new COVID-19 cases in those countries.

On Friday, the U.K. Health Security Agency said BA.2 has a "substantial" growth advantage over the original Omicron strain. The subvariant has spread faster in all regions of England where there were enough cases to conduct an analysis, the agency said in a report.

A preliminary evaluation found that BA.2 doesn't appear to change how well the vaccine works compared to the original Omicron strain, the agency said. A booster dose was 70% effective at preventing symptomatic illness for BA.2, compared with 63% for the original Omicron strain.

The CDC also said on Friday that although the subvariant has become more common in some countries, it is currently at a low level in the U.S. and doesn't appear to be more serious.

"Currently there is no evidence that the BA.2 lineage is more severe than the BA.1 lineage," Kristen Nordlund, a CDC spokesperson, told CNBC.

The WHO hasn't labeled BA.2 a "variant of concern" so far but will continue to monitor it. WHO officials have said that new variants will arise as Omicron spreads across the world.

"The next variant of concern will be more fit, and what we mean by that is it will be more transmissible because it will have to overtake what is currently circulating," Maria Van Kerkhove, the WHO's COVID-19 technical lead, said during a livestream last week.

"The big question is whether or not future variants will be more or less severe," she said.


CNBC: "The latest Covid variant is 1.5 times more contagious than omicron and already circulating in almost half of U.S. states." "BA.2 Lineage Report, updated Jan. 29, 2022."

U.K. Health Security Agency: "COVID-19 variants identified in the UK, updated Jan. 28, 2022.'

U.K. Health Security Agency: "SARS-CoV-2 variants of concern and variants under investigation in England, Technical briefing 35, Jan. 28, 2022."

WHO: "LIVE: Q&A on #COVID19, Omicron, #VaccinEquity. #AskWHO, Jan. 25, 2022."


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