BA.2 Sub-Variant of Omicron: What Is It? How Contagious Is It?

The sub-variant has mostly been identified in Asia and Europe till now. Does it cause a more severe illness?

The World Health Organization (WHO) has on 1 February, Tuesday pointed that the BA.2 sub-variant has been detected in 57 countries, predominantly in Asia and Europe.

The director of the National Centre for Disease Control (NCDC) had stated on Thursday, 27 January that the BA.2 sub-variant of the strain, is more prevalent in India now.

How contagious is it? Does it cause a more severe illness? Here is all we know about it:

What is BA.2?

BA.2 is a sub-variant of Omicron and has been spreading since November 2021.

The B.1.1.529 lineage of COVID-19 was named Omicron. However, it was discovered later that this lineage has certain sub-variations. The three most common types are:

• B.1.1.529.1 (BA.1– currently predominant)

• B.1.1.529.2 (BA.2 – raised concerns)

• B.1.1.529.3 (BA.3)

Does BA.2 cause more severe illness than BA.1?

WHO has on 1 February, Tuesday said that the BA.2 sub-variant does not seem to be more severe than BA.1.

It could be more infectious, but there has been no evidence that flags it as more harmful.

Is it more contagious?

According to Danish studies, BA.2 is more transmissible than the current BA.1 variant of Omicron.

It has the potential to globally replace the BA.1 variant of Omicron.

In which countries is BA.2 majorly detected?

BA.2 is detected in about 57 countries now. This list includes the following countries:

• Denmark

• Britain

• India

• Sweden

• Singapore

• Philippines

• Nepal

• Qatar

• Pavlin

Do BA.1 and BA.2 possess different properties?

The Statens Serum Institut of Denmark has said that the difference between BA.1 and BA.2 is more than that of the Wuhan variant and Alpha variant. This may lead to different properties in terms of:

• Infectiousness

• Vaccine efficiency

• Severity

• Immune escape

However, till now, there is no concrete information about the difference in their properties.

Is it a variant of concern?

No. So far, the United Kingdom (UK) Health Security Agency has termed this as a "variant of surveillance" or "variant under investigation."

Does BA.2 reduce vaccine efficiency?

Efficacy of vaccines are generally lowered against the Omicron variant but they provide similar protection against both BA.1 and BA.2.

(Inputs from Reuters, Hindustan Times, and The Indian Express.)