After India witnessed cases of the sub-variants of Omicron, Dr Rajeev Jayadevan, co-chairman of the Indian Medical Association's national task force on May 24 said that these newly-detected sub-lineages will not cause a surge in infections but people still need to be vigilant.

"The sub-variants of Omicron (BA.4 and BA.5) are not going to cause a surge in cases, still, we need to be vigilant. You know that Omicron took off at a much higher rate in many countries, including India, but South Africa's experiences reassure us that these two sub-lineages are not going to cause a large scale problem if we are careful enough," Dr Jayadevan told ANI.

He clarified that BA.4 and BA.5 are not new viruses, rather, these are just sub-lineages of the Omicron variant of COVID-19 infection. "Basically, Omicron took off from one branch of the genomic tree and these are the smaller branches of Omicron itself so they are not new viruses. We know that this virus is continuously adapting to the human host in order to escape our immunity and also to travel faster between people, said Dr Rajeev.

Dr Rajeev also said that sub-variants BA.4 and BA.5 caused a surge in cases in South Africa, however, cases also came down rapidly. He said, "BA.4 and BA.5 caused a surge in cases a couple of weeks ago, but they came down rapidly. They did not go as high as the Omicron did back in November, December last year."

On evading protection from Omicron, he said, "Omicron is unlike other variants as its every sub-lineage is evolving to escape itself. We are more concerned about, will there be a whole new variant coming from a completely different branch of the genomic tree? And that is the concern we have because now Omicron has run its course for about six, seven months since November."

"We should be on the lookout for anything new, anything unusual, unusual clusters must go for sequencing," he warned. BA.4 and BA.5 are subvariants of the Omicron variant circulating globally. These were reported first from South Africa earlier this year and are now reported from several other countries. These variants have not been associated with disease severity or increased hospitalisation.

The first case of BA.4 and BA.5 subvariants of the Omicron variant of COVID-19 have been found in Tamil Nadu and Telangana respectively confirmed by the Indian SARS-CoV-2 Genomics Consortium (INSACOG) on May 22.