AY.4.2 not detected in Maharashtra samples: state health officials
The new descendant of the Delta variant of novel coronavirus – AY.4.2 – that is closely being monitored in the United Kingdom has not been found in Maharashtra, state health officials said on Wednesday.
The new descendant of the Delta variant of novel coronavirus – AY.4.2 – that is closely being monitored in the United Kingdom has not been found in Maharashtra, state health officials said on Wednesday. This Delta variant sub-lineage was labelled as a Variant Under Investigation (VUI) by the UK Health Security Agency (UKHSA) on October 20 and is said to have “modestly increased growth rate compared to Delta”.
Principal secretary of the state’s public health department Dr Pradeep Vyas said the AY.4.2 sub-lineage has not been detected in any sample from Maharashtra so far.
State’s epidemiologist Dr Pradeep Awate reiterated it. “AY.4.2 has two additional mutations along with the Delta and the AY.4 mutation. None of the samples from Maharashtra have found these additional mutations,” said Awate.
The Delta variant (B.1.617.2) continues to be a concern globally as well as in Maharashtra. As of October 25, nearly 73% samples from the state that were sent for genome sequencing under the Indian SARS-CoV-2 Genomics Consortium (INSACOG) and to the Council of Scientific and Industrial Research–Institute of Genomics and Integrative Biology (CSIR–IGIB) had the Delta variant. Nearly 5.5% samples had the Delta sub-lineages starting from AY.1, AY.2 and so on.
AY.4.2 INFREQUENT IN INDIA
Globally, the Phylogenetic Assignment of Named Global Outbreak (PANGO) nomenclature is being used by researchers and health agencies to classify the SARS-CoV-2 genomes and variations. Based on the PANGO classifications, 17 AY.4.2 sequences were found in India. These 17 cases also reflected on GISAID, an open-source database tracking the genomic signature of coronavirus variants. However, INSACOG on Wednesday clarified that none of these sequences had both the mutations together. “Manual analysis of these 17 sequences has revealed that 8 sequences have only Spike_Y145H, 2 sequences have only Spike_A222V, whereas the remaining 4 sequences do not have either of the mutations,” the INSACOG release stated. “These 17 samples included 10 from Gujarat, two from Assam, and one from Maharashtra among others. But all these samples were from May, June and July,” said Dr Sujeet Kumar Singh, director of the National Centre for Disease Control (NCDC).
The INSACOG also stated that based on the case definition used by UK health authorities, AY.4.2 is very infrequent (below 0.1%) in India. “Most sequences from India that are being classified by PANGO as AY.4.2 have only either Y145H or A222V in Spike, not both mutations appearing together,” it said.
AY.4 to AY.33
Among the AY sub-lineages, AY.4 has been dominant in Maharashtra. But INSACOG on Wednesday said that many cases earlier labelled as AY.4 are now reclassified at AY.33 in the new revised system. Maharashtra’s task force member Dr Shashank Joshi said genome scientists are not in agreement with the mutation classification and terminology as far as the AY.4.2 is concerned. “At the moment, we largely have immunity for Delta and Delta derivatives as it has been the dominant strain. Therefore, it’s unlikely that the new sub-lineage will pose a threat, but we have to constantly keep a vigil,” he said.
Experts said the AY.4.2 scenario should be looked at from a global perspective. “This particular mutation is creating a problem in UK, north China, Spain, Germany and parts of Europe. But we still know little about its transmission and pathogenicity, so we have to keep a close watch on the global scenario while assessing our own situation,” said infectious disease expert Dr Om Srivastava who is also a member of the state’s task force.