A 78-year-old woman from an eastern suburb was the first person in Mumbai to have been infected by the Delta-plus variant, while the other case was in Thane, according to the Brihanmumbai Municipal Corporation (BMC).
This information comes after state health minister Rajesh Tope said on Monday that two cases of this variant had been found in Mumbai. Civic officials said the woman was asymptomatic and in home isolation, did not have any travel history and had completely recovered, without suffering post-Covid complications.
Additional Municipal Commissioner Suresh Kakani said the woman had been diagnosed with Covid in April, following which her swab sample was sent for whole genome sequencing to the National Institute of Virology (NIV). Since she lived in a joint family, some of her family members had also been infected. Subsequently, samples from all her afflicted kin were collected and sent to the NIV. The civic body has been sending 50-100 samples to the NIV for genome sequencing every week.
Dr Trupti Gilada, consultant physician for Infectious Diseases, Masina Hospital, said the Delta-plus variant is a ‘variant of interest’. Only if it is proven that it is either more infectious, more virulent or is evading vaccine immunity will it be labelled a ‘variant of concern’.
She said the extent of protection from the Delta-plus variant offered by Covishield and Covaxin still remains to be completely understood. “There is always the looming possibility of the emergence of new variants whose behaviours are unpredictable. Therefore, it is very important to ensure Covid-appropriate behaviour at all times,” she said.
Since May, the state government has sent around 7,500 samples for genome sequencing to Pune’s National Institute of Virology and New Delhi’s CSIR-Institute of Genomics & Integrative Biology (IGIB). So far, 21 samples in the state have been detected with the Deltaplus variant.
“All index cases with this variant will be closely studied. Their travel history, vaccination status, health condition and the testing of high- and low-risk contacts will be done,” Tope said.
The highly infectious Delta variant (B.1.617.2), which is believed to have driven the second wave, has further mutated to form the Delta plus or ‘AY.1’ variant. Deltaplus carries all mutations present in Delta—that was first detected in India and is currently found in 80 countries—plus an additional one, ‘K417N’. The mutation is in the spike protein, the region that interacts with the human cell. Experts have cautioned that since it has emerged from the highly transmissible Delta variant, there is every reason to stay extra vigilant.