BA.2 Omicron Subvariant Possibly Severe As Delta, Lab Studies Show

Lab research from Japan also shows BA.2 can evade vaccines, but a booster is 74% effective against symptomatic Covid-19 infection.

KUALA LUMPUR, Feb 21 – Lab experiments from Japan show that an Omicron subvariant dubbed BA.2, already more contagious than Omicron, may be able to cause severe disease from Covid-19 like the Delta variant.

CNN reported that like Omicron, BA.2 has a large degree of vaccine evasion, but a booster shot is 74 per cent effective against symptomatic Covid-19.

The new study also reportedly found that BA.2 was resistant to monoclonal antibody treatments, including sotrovimab that’s used to treat Omicron.

The findings were posted as a preprint on the bioRxiv server before peer review. 

“There is no evidence that the BA.2 lineage is more severe than the BA.1 lineage. CDC continues to monitor variants that are circulating both domestically and internationally,” Dr Rochelle Walensky, director of the United States’ Centers for Disease Control and Prevention (CDC), was quoted saying last Friday. 

“We will continue to monitor emerging data on disease severity in humans and findings from papers like this conducted in laboratory settings.”

American epidemiologist Dr Eric Feigl-Ding, however, tweeted his concern about BA.2, as he called for it to be upgraded into a variant of concern.

He noted the study’s findings that BA.2 was also resistant to immunity from prior infection with Omicron’s original BA.1 lineage, describing BA.2 as the worst “of four worlds” – higher transmissibility, greater vaccine escape, resistant to immunity from prior infection, and more severe disease.

“We must act quickly with high urgency to stop the rise of BA2. We have not learned from the past — if we ignore BA2, we could be facing another / continued wave of excess deaths. Let’s learn from history rather than repeat it,” he tweeted earlier today.

“The other urgency is that vaccine effectiveness is only high with boosters in face of #Omicron whether BA1 or BA2. But most folks aren’t boosted in most countries. Thus are we truly prepared for #BA2 given we know BA1 infection immunity isn’t as good versus BA2?”

CNN highlighted real-world data that showed mixed findings on the severity of BA.2 in countries where the subvariant is now dominant, pointing out that hospitalisations and deaths are rising in Denmark, but countries like South Africa and the United Kingdom are seeing declining hospitalisations.

The World Health Organization (WHO) estimates BA.2 to be about 30 per cent more transmissible than Omicron. The subvariant has already been reported in 74 countries.

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