Tamil Nadu's first case of covid-19 Omicron BA. 4 sub lineage variant is a teenager and a part of a four-member family with no travel history and had taken two jabs of the vaccine against the virus. The 19-year-old college student from neighbouring Chengalpattu district, who had contracted Omicron BA. 4 sub lineage variant, has fully recovered and this strain has not spread to other parts of Tamil Nadu, state Health and Family Welfare Principal Secretary Dr J Radhakrishnan said on Monday, May 23.
The teenager, among the family of four who was infected with the contagion, did not have any travel history. Epidemiologically it has not been detected how this particular strain, infected her, he said. "The strain could have probably been circulating around. Her's is the only case in the state. She has fully recovered," Dr Radhakrishnan told PTI.
Interestingly, her mother, aged 45, who along with her daughter developed a mild flu like illness on May 4, voluntarily underwent RT-PCR test at a private lab, and had BA.2 sub-lineage while her daughter had BA.4 variant. Both were caused by the Omicron variant of SARS-CoV-2.
The BA.2 is the predominant variant reported in 73% of the samples sequenced for Whole Genomic Sequencing (WGS) of covid-19 samples in Tamil Nadu. The recent clusters in IIT Madras and Sri Sathya Sai Medical College were due to the BA.2 variant of Omicron.
"Both the mother and daughter self-quarantined and recovered in three days," Dr Radhakrishnan said and added that the government of India had announced that BA. 4 is not a cause of panic.
The girl's father and grandmother did not have symptoms. Three among this family residing in a gated community at Navalur, OMR, Chengalpattu district, had completed 2 doses of the vaccine while the grandmother had taken a single shot.
The samples of mother and daughter were sent to NEERI, Nagpur on May 13 for WGS and the results were obtained on May 19.
On Sunday, the IndianRS-CoV-2 Genomics Consortium (INSACOG) had said the teen had been found infected with the BA.4 sub-variant of the virus.