Is AY.4 Coronavirus Variant More Infectious Than Delta? Know What Scientists Say

New Delhi: Amid fears of AY.4 a sub-lineage of the Delta variant of the Coronavirus, Rakesh Mishra, former director of the Centre for Cellular and Molecular Biology (CCMB), said on Monday, there is no evidence to suggest that it has a higher infectivity rate than Delta, and is not a new variant.

Notably, six persons in Indore district of Madhya Pradesh were found infected with AY.4, Chief Medical and Health Officer (CMHO) of the state B S Saitya said, adding all the six were fully vaccinated and have recovered after treatment.

“There is no evidence or observation to suggest that there are more vaccine breakthrough or reinfections or more infectivity due to AY.4. At the moment, it does not look like it,” Mishra told PTI.

Mishra, who headed the Hyderabad-based CCMB that is at the forefront of genome sequencing of the coronavirus and is now Director of the Tata Institute for Genetics and Society in Bengaluru, however, stressed that observing COVID-appropriate behaviour is still very important as COVID-19 is yet to reach the pandemic stage.

Recent relative expansion of the AY.4 lineage, compared to B.1.617.2, in INSACOG data should be seen in the light of global evidence regarding no substantial difference between the Delta lineages so far, INSACOG, a genome-sequencing consortium, said in its October 4 bulletin. However, the matter continues to be monitored and correlated clinically, it added.

Globally, the AY.4 lineage is most frequently seen, with the highest levels in the UK and evidence does not suggest any Delta lineage being substantially different from the others and as of now, the micro-lineage analysis is only for epidemiological surveillance, the INSACOG bulletin said. 

“There is presently no additional clinical or public health concern regarding these sub-lineages,” it said. INSACOG’s September 13 bulletin said Delta and the Delta sub-lineages continue to be the main VoC in India.

“AY.4 is the most frequently seen sub-lineage in recent sequences from India as well as globally,” it added.