The World Health Organization has announced it has discovered a highly contagious sub-variant of the Omicron coronavirus strain.
According to the United Nation’s health body, the BA.2, also known as the “stealth variant”, has been detected in 57 countries, including the UK, Sweden, India and the US.
According to Denmark’s Statens Serum Institut (SSI), BA.2 infections rose to account for about half of the country’s reported Covid cases in January 2022.
India is another country where BA.2 is rapidly replacing the Delta and Omicron BA.1 variant, according to recent health data. It is already the dominant variant in several states and likely drove the country’s recent wave of infections.
The Philippines’ Department of Health (DOH) has also reported that the sub-variant was identified in several samples collected in January 2022. The UK Health Security Agency (UKHSA) have also identified at least 1000 confirmed cases of BA.2.
Omicron Variant And Sub-Variants
The highly contagious Omicron variant which was first detected in November 2021, accounts for more than 93 percent of all coronavirus infections recorded in the past months.
Fortunately, the variant also known as B.1.1.529, is generally known to cause less severe sickness, compared to previous variants like Delta, Beta and the original sub-lineage, Alpha.
The Omicron variant which has been detected in over 165 countries across the globe, has several sub-lineages: BA.1, BA.1.1, BA.2 and BA.3.
Up until now, the BA.1 has been dominating with the WHO estimating it makes up to 96% of sequenced Omicron cases.
However, the BA.2 is beginning to catch up fast.
Difference Between BA.1 And BA.2
The original version of Omicron had specific genetic features that allowed health officials to rapidly differentiate it from Delta using a certain PCR test because of what’s known as “S gene target failure”.
BA.2 doesn’t have this same genetic quirk.
A person with BA.2 will still test positive for the coronavirus on a PCR test, but their case won’t be flagged as BA.2 unless their original sample goes through genetic sequencing.
“It’s not that the test doesn’t detect it; it’s just that it doesn’t look like Omicron,” Dr Wesley Long, a pathologist at Houston Methodist in Texas told the Associated Press.
How Transmissable Is BA.2?
A study of 8,500 households and 18,000 individuals conducted by Denmark’s SSI found that BA.2 was “substantially” more transmissible than BA.1.
However, the preliminary assessment published in a UK study found no evidence that vaccines would be any less effective against symptomatic disease for the original variant as well as its sub-variant.
Is BA.2 more dangerous?
There is no data to suggest that BA.2 leads to more severe disease than previous Omicron sub-variants. Experts however have continued to assure the public that vaccines will continue to be highly effective against severe illness, hospitalisation, and death.