AY.4.2 dubbed as new ‘Delta Plus’ variant. But can it become dominant?

Union health minister Mansukh Mandaviya said on Tuesday that a government panel of experts was looking into a Delta coronavirus subvariant, AY.4.2, that believed to have triggered an increase in the coronavirus disease (Covid-19) cases in the United Kingdom.

“A team is investigating the new Covid-19 variant AY.4.2 … ICMR and NCDC teams study and analyse the different variants,” Mandaviya told mediapersons.

The UK health security agency said last week that it was investigating AY.4.2 as it was possibly more transmissible than Delta, though there was no evidence that it caused more severe disease or rendered vaccines ineffective.

It was designated a variant under investigation (VUC) by the UK agency.

What is AY.4.2 sub-lineage?

Matthew Bashton and Darren Smith, from Northumbria University in Newcastle, said that 75 AY lineages of the coronavirus have been identified till now, each with different additional defining mutations in their genome.

Talking about these in The Conversation, the duo said one of these variants – the AY.4 – has been steadily growing in proportion in the UK over the last few months, accounting for 63 per cent of new cases in the last 28 days.

“The defining change in AY.4 is the mutation A1711V, which affects the virus’s Nsp3 protein, which plays a number of roles in viral replication. However, the impact of this mutation is unknown,” Bashton and Smith said in their article.

While Bashton is Senior Fellow in Computational Biology, Smith is Professor of Bacteriophage Biology at Northumbria University.

They added that the AY.4.2 sub-lineage is defined by two additional genetic mutations, Y145H and A222V, that affect the spike protein.

AY.4.2 has grown steadily in volume and has also been observed in a few European nations like Denmark, Germany and Ireland. Till October 20, the AY.4.2 – first detected in July – had affected than 15,000 people in the UK.

Is there a need to be worried?

Bashton and Smith argue that despite introduction into several European countries, AY.4.2 has failed to take hold, dropping off the radar in Germany and Ireland – though it is lingering in Denmark. “This would suggest its ability to get around immunity isn’t any greater than Delta’s. Equally, it might just be that there wasn’t enough of AY.4.2 arriving in these places for it to take hold,” both argue.

They also said that it’s too early to tell if this is the beginning of the next dominant lineage, adding that any ability it might have to escape immunity needs to be confirmed by experimental work.

Concerns raised in India

Rajasthan chief minister Ashok Gehlot asked the central government on Monday to prepare and issue standard operating procedures (SOPs) to check the spread of AY.4.2.

The chief minister added that the government should learn from previous experiences and make full preparations to deal with the new variant. “Initially, there were only a few cases of the Delta variant but it did not take time to spread across the country,” he said.

INSACOG, a consortium of labs that is engaged in sequencing coronavirus variants, have said that there is no spike in Covid-19 cases due to the AY.4.2 subvariant.