DNA Explainer: Why Stealth Omicron has triggered record number of cases

Omicron's sub-variant BA.2 also known as Stealth Omicron is currently creating havoc in many countries. As the name implies, it is cryptic because its ancestor has several common mutations with the BA.1 Omicron type. But BA.2 does not have a genetic deletion on the spike protein, making it difficult to identify in RT PCR tests.

This strain takes a lot of time to be traced, hence it has been called stealth or secret variant. On February 22, 2022, the World Health Organisation (WHO) issued an official statement on this variant for the first time. WHO stated that BA.2 would be considered a type of concern based on available data on transmission, severity, re-infection, diagnosis, therapeutics and effects of vaccines.

Read | 4th wave of Covid: Here's everything to know about Stealth Omicron

Why is BA.2 more contagious?

This strain of virus is not detectable in tests like RT-PCR due to its genetic composition.

WHO said that researchers is trying to understand the reason for the development of this variant.

However, preliminary data suggest that BA.2 is naturally more permeable than BA.1 Omicron.

Symptoms of BA.2 

The stealth sub-variant of the Omicron variant has not shown any distinct symptoms so far.

But it has been observed that the Covid-19 virus affects different people in different ways.

This makes it difficult to isolate the symptoms of a particular variant or subvariant.

However, experts suggest early symptoms of stealth variants can be dizziness and tiredness.

Symptoms can be observed two to three days after exposure to the BA.2 virus.

Other symptoms include mild fever, runny nose, difficulty in breathing, sore throat, headache, body aches.

WHO cities reasons behind the wave

Mutations found in the spike protein of the BA.2 sub-variant of Omicron were not detectable in the rapid PCR test.

There is also the concern that BA.1 and BA.2 together can create a new look. There have been two such cases in Israel.

BA.2 infections Worldwide

BA.2 is currently responsible for the surge in new wave of Covid-19 in China.

In Hong Kong cases have crossed one million, 97% of which have been reported in the recent wave.

There the virus has taken 5,401 lives so far, which is more than the deaths (4,636) since the outbreak.

The biggest concern is increasing number of cases in South Korea, where the tally has crossed 9 million.

Of these, 16% or more than 14 lakh cases were recorded in three days between Thursday and Saturday.

In Europe, France, England and Italy have seen an increase of more than 30% in cases within a week. 

More than two lakh Covid-19 cases are being reported daily in Germany due to the BA.2 sub-variant.

Cases of Covid are also being seen more in France, Switzerland, Italy and the Netherlands.

Reports suggest the BA.2 version accounts for more than half of the new cases in Germany.

Around 11% of the total cases reported in the United States are due to the Stealth Omicron.

BA.2 has overtaken the sub-variant BA.1 in many countries including China and Europe.

The World Health Organisation (WHO) said that this jump in Covid figures is the 'tip of the iceberg'.

Misconception on Omicron

The biggest misconception is that 'Omicron is mild' variant. 

The assumption that Omicron is the last variant is also wrong. 

Pandemic is not over and more people who are not fully vaccinated are coming in the grip.