Home/ Science / Health/  What is 'stealth Omicron BA.2'; is it really hard to track? All that you need to know

Even as the Omicron COVID variant continues to puzzle us, another sub-strain of the variant - BA.2, also known as stealth Omicron, has emerged. This sub-variant has already spread across 50 countries including India. And experts suggest that BA.2 is only more contagious than the earlier detected but also harder to detect. So, should we be worried? 

What is stealth Omicron?

This version of the coronavirus, which scientists call BA.2, is widely considered stealthier than the original version of omicron because particular genetic traits make it somewhat harder to detect.

BA.2 has lots of mutations. About 20 of them in the spike protein that studs the outside of the virus are shared with the original omicron. But it also has additional genetic changes not seen in the initial version.

Also read: Stealth Omicron BA.2 spread faster than BA.1 but there's a catch: UK study. Read here

How is it different from Omicron's BA.1 variant? 

A recent study by UK Health Security Agency (UKHSA) has suggested BA.2 sub-lineage of the COVID variant spreads much faster than the BA.1 strain. But, it seems to show higher vaccine protection.

After two doses, vaccine effectiveness was 9% and 13% respectively for BA.1 and BA.2, after 25 weeks. This increased to 63% for BA.1 and 70% for BA.2 at 2 weeks following a third vaccine, the study pointed out.

Also read: ‘Stealth’ Omicron variant spreads to 50 countries: All you need to know 

Should you be worried?

An initial analysis by scientists in Denmark shows no differences in hospitalisations for BA.2 compared with the original omicron. It's also unclear how well treatments will work against it.

Doctors also don't yet know for sure if someone who's already had COVID-19 caused by omicron can be sickened again by BA.2. But they're hopeful, especially that a prior omicron infection might lessen the severity if that happens.

How significantly has it spread across India?

Earlier this week, the Centre pointed out, the BA.2 subvariant of the Omicron coronavirus is more prevalent in India now.

An official said BA.1 and BA.2 were found in sequenced samples while BA.3 has not been found yet. "We were getting more samples of BA.1 earlier mostly found in travellers but now we are seeing that BA.2 has become more prevalent in the community," he said.

With agency inputs

Also read: What is stealth Omicron, can sub-variant BA.2 escape immune system? WHO explains

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Updated: 30 Jan 2022, 04:07 PM IST
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