‘Omicron is also BA.3’: what the WHO says on signs of COVID severity in people

“I would like to reiterate that Omicron is a type of concern and we are tracking Omicron in several subcategories. The most prominent ones found worldwide are BA.1, BA.1.1 and BA.2. BA.3 and There are other sublines as well,” said Maria Van Kerkhove, WHO’s top infectious disease expert.

She said that many people had heard of a Japanese study that turned out to be an impression. “And this study is an experimental study looking specifically at hamsters. And what they were looking for was whether or not, experimentally, within hamsters, a sign of causing more severe disease under these experimental conditions.” We’re also seeing seriousness in what we call the real world.”

Kerkhov said that the WHO is also looking for signs of seriousness in people. “And are we seeing any difference in severity at the population level in terms of an increased risk of hospitalization for people infected with BA.2 compared to BA.1? And it’s been evaluated from many countries that we are using BA. Not seeing a difference in severity of BA.1 compared to .2.”

So there is a similar level of severity as it relates to the risk of hospitalization, she said, which is really important because, in many countries, they have a substantial prevalence of both BA.1 and BA.2.

“And in those countries, they have seen no change in the severity of BA.1 compared to BA.2. So in addition to experimental studies, we look at real-world data,” she said.

What the Japanese lab study says:

recently Japanese Laboratory Studies indicated that the Omicron subvariant BA.2 may cause more severe diseases than the previously identified BA.1. The Japanese study looking at the effects of Omicron ba.2 on hamsters was trying to find out if there were any signs of serious illness. The preprint suggested that BA.2 could cause “serious disease in hamsters”.

However, looking for signs of severity in humans, in terms of increased risk of hospitalization in people infected with BA.2 compared to BA.1, it was observed that humans did not have greater severity.

Key highlights of Japanese Studies on Omicron BA.2:

Important things about Subvariant BA, 2, also known as Stealth Omicron, which was identified by the Japanese team –

1) While BA.2 may have characteristics that enable it to cause “severe disease”, this sub-variant shows immunodeficiency properties similar to BA.1. Also “Stealth Omicron” is resistant to treatments such as monoclonal antibodies.

2) The researchers said that although BA.2 is treated as an Omicron variant, its genomic sequence is significantly different from that of BA.1. “And, this suggests that the virological characteristics of BA.2 are different from those of BA.1,” the study states.

Although the WHO later clarified that stealth omicrons can cause serious infections in hamsters, studies among humans show that the level of severity is similar for both subtypes.