CHENNAI: Tamil Nadu reported its first case of BA.4 subvariant of Omicron, which reportedly led to a surge in Covid-19 cases in a few European countries and triggered the fifth wave in South Africa. This is the second case of BA.4 subvariant of Omicron in India; the first case was reported in Telangana recently. The detection, however, will have to be reconfirmed by the Union Health Ministry.
Speaking to reporters at the King Institute in Guindy, Health Minister Ma Subramanian said an initial report showed that the subvariant was detected in a 19-year-old girl who was part of a family cluster at Navalur in Chengalpattu district. They had no travel history. He said the health department was continuously monitoring the cases and there was nothing to panic about. The State Whole Genome Sequencing Lab has sent the samples to the National Environmental Engineering Research Institute (NEERI) in Nagpur.
Of the four family members -- father, mother, daughter, and grandmother -- the mother (45) and the daughter (19) developed mild flu-like illness on May 4. They voluntarily got tested at a private lab and the samples returned positive for Covid-19. Since it was a family cluster, the samples were sent for Whole Genome Sequencing (WGS).
The result of WGS on May 19 showed that the mother was infected by BA.2 subvariant of Omicron and the daughter by BA.4 subvariant, Subramanian said. The mother and daughter were fully vaccinated and no new case was reported. They recovered in a few days and returned to normal life, a statement from the health department said
Health Secretary J Radhakrishnan who inspected the area and met the family said they are doing fine. It is important to get vaccinated to be protected from any variant. People should also continue to follow Covid-19 appropriate behaviour, he said.
TS Selvavinayagam, Director of Public Health and Preventive Medicine, said: "Mutation of the virus is a natural process and BA.4 is like any other subvariant of Omicron. But, following the existing pandemic control measures are important to keep it in check. We have been stressing that the public should take booster doses, given that the immunity could wane with time. Camps are being held regularly and we have also been requesting people to come forward to take booster doses."
Meanwhile, data from the health department showed that in May, 82% of samples tested showed BA. 2 variant of Omicron, 7% BA.3 variant, 4% are BA.2.10 variant, and BA.4 are 0.7 % (one case).
Dr T Jacob John, a retired professor and head of departments of clinical virology and microbiology at CMC Vellore, said: "In countries where BA.1 was the dominant variant, BA.4 caused an increase in cases. Such an increase is unlikely in India as BA.2 was the major variant here. We should, however, exercise caution and continue genome sequencing. While we have vaccinated a large number of people, the decrease in the number of people coming forward to take the booster doses is worrying. Immunisation is not complete without the booster dose."
A total of 3,328 samples were taken from January to May and sent for WGS at the State Public Health Lab on the DMS campus. Of this, 96% belonged to Omicron. BA.2 was reported in 73% of the samples. Also, BA.1 was reported in some samples, the data showed. Also, samples from IIT- Madras and Sri Sathya Sai Medical College clusters tested positive for BA.2 variant of Omicron, the statement said.