After a recent Japanese lab study indicated that Omicron subvariant BA.2 can cause more severe diseases than the previously identified BA.1, World Health Organisation (WHO) officials explained that research suggests that the stealth omicron can cause serious infection in hamsters, but studies among the humans show that the level of severity for both the subvariant is same. However, speaking about the Japanese lab study further, the WHO official said, these studies are very critical in looking for severity signals.
The Japanese study which was looking at the effect of Omicron BA.2 on hamsters was trying to find out if there is a signal of severe disease. Now, these studies are very critical to be done. And, this preprint suggests that BA.2 can cause severe disease in hamsters, said WHO’s Maria Van Kerkhove.
However, while looking for severity signals in humans, in terms of the increase in risks of hospitalisation among the people who have been infected with BA.2 compared to BA.1, it has been observed that we are not seeing more severity among humans. Both sub-variants cause a similar level of severity, the official added.
Three things that Japanese lab study said on Omicron BA.2
The three crucial things about the subvariant BA,2, also known as stealth Omicron, that the Japanese team has identified are – BA.2 may have features that make it capable of causing serious illness, it shows immune escape properties just like sub-variant BA.1. Further stealth Omicron is resistant to treatments like the monoclonal antibody.
The researchers said although BA.2 is considered as an Omicron variant, its genomic sequence is heavily different from BA.1. “And, this suggests that the virological characteristics of BA.2 are different from that of BA.1,” they added.
World Health Organisation had previously warned that the BA.2 is surging faster than the previously identified strain. And in case there is another Omicron wave, then we could see further infections of BA.2.
WHO also pointed out that all other coronavirus variants, including alpha, beta and delta, continue to decline globally as omicron crowds them out. Meanwhile, the subvariant BA.2 appears to be “steadily increasing” and its prevalence has risen in South Africa, Denmark, the UK and other countries.