AY.4.2 Delta subvariant: All you need to know

When countries around the world thought that there was a slight relief from the Covid-19 pandemic, a new variant of the virus has brought back fear across the globe.

Cases of the AY.4.2 variant, a sub-lineage of the Delta variant have been reported in many countries, and is claimed to be highly transmissible but less fatal.

According to a report by the NDTV, The UK Health Security Agency (UKHSA) made a classification that the Delta sub-lineage AY.4.2 showed an increased growth rate in the UK in the recent months.

Also read: How worried should we be about the new AY.4.2 lineage of the coronavirus?

According to the UKSHA, “There is some early evidence that it may have an increased growth rate in the UK compared to Delta”. However, “more evidence is needed to know whether this is due to changes in the virus' behaviour or because of epidemiological conditions” the report added.

What is the AY.4.2 variant?

AY.4.2 is a descendant of the Delta variant of Covid-19. The Delta variant, also known as B.1.617.2, was first identified in India in October 2020. The AY.4.2 sub-lineage contains two mutations in its spike protein - A222V and Y145H. According to the report, the UKHSA gave Delta sub-lineage AY.4. the official name VUI-21OCT-01.

Countries that have reported the AY.4.2 variant:

The United Kingdom has reported 96 per cent cases of AY.4.2, followed by Denmark and Germany at 1 per cent each. The new variant has also been reported in the US, Israel, and Russia.

The Israel ministry stated on October 19 that the country had confirmed a case of AY 4.2, with an 11-year-old boy arriving from Europe being the carrier. Similarly, Russia, too, reported “isolated cases” of the Delta sub-variant last week NDTV reported.

Also read: Two suspected cases of AY.4.2 variant of Covid sent for genome sequencing: Sudhakar

Is AY.4.2 dangerous?

According to UKHSA, though evidence on AY.4.2 is still emerging, as of now, it does not appear to cause more severe diseases. The sub-lineage does not render the vaccines currently deployed any less effective against it.

Effect on immunity:

A report by the Scroll.in said that the mutation is within an “antigenic supersite” of the spike protein – a part of the protein that antibodies frequently recognise and target. This part of the spike protein has already been modified once before by a mutation in Delta’s genetic material, and this possibly contributes to Delta’s greater ability to escape immunity, as antibodies have a harder time targeting it. However, it is yet to be formally reviewed.