Mumbai: Amid global concern of rising Covid reinfections due to newer Omicron subvariants, the latest Covid genetic sequencing report in Mumbai found two highly infectious subvariants XBB and XBB.1 in the city for the first time as well as a patient who has had Covid not once or twice, but four times in the last 31 months.
XBB and XBB.1 were found in almost 30% of the 234 cases analysed at the BMC-run Kasturba lab this time around; one of the XBB cases is a 62-year-old doctor from Delhi identified as Dr Veena Aggarwal.
Dr Aggarwal’s samples were studied during each of her four infections for research purposes by doctors in Mumbai’s Nair Hospital and/or Delhi, and there is proof to say she was first infected by the Wuhan strain, then the UK strain called Alpha, followed by Delta strain and now XBB strain.
“In 2021, barely 10 days after I recovered from the Alpha strain, I was down with the Delta variant,” Dr Aggarwal told TOI. Her infections were a part of the first research papers to establish Covid reinfections despite vaccination, said main researcher Dr Jayanthi Shastri from Nair & Kasturba Hospitals.
However, Dr Shastri, who is in charge of BMC’s genomic laboratory at Kasturba Hospital, said all XBB cases detected in Mumbai now have had mild symptoms. “There have been no deaths due to XBB,” she said.
The 16th round of genome sequencing in Mumbai, however, found two deaths among elderly patients suffering other Omicron subvariants.
The latest round has shown that Omicron is the only variant in circulation in Mumbai. “Around 15% of samples were detected with XBB variant, while another 14% with XBB.1 subvariant,” said BMC additional municipal commissioner Dr Sanjeev Kumar.
World Health Organisation discussed XBB and XBB.1 – recombinant versions of Omicron’s worrisome sublineages – but stopped short of naming them as variants of concern.
Maharashtra surveillance officer Dr Pradip Awate said XBB.1 has been found in other parts of the state too. “A small deviation in the genetic structure leads to a new name. But we have decided to not go into detailed names and call the entire sub-group as XBB,” he told TOI.
Dr Awate also said reinfections are increasing. “Of 36 XBB cases we analysed, 17 were cases of reinfections,” he said. However, there is no cause for worry as most patients had mild to no symptoms. This is expected in the endemic stage of the disease,” he added.
Dr Shastri said the latest genomic sequencing report proves yet again that vaccination helps. Of 234 infected, 87 had not got a single dose of the Covid-19 vaccine and 15 of them needed hospitalisation. In comparison, seven of the 147 who had got the vaccine needed hospitalisation.
BMC public health department officials said that although there is no reason to panic, people should wear a mask. “Although the XBB and XBB1 strains can be conclusively proved by genome sequencing, they can also be identified by PCR kits such as Omisure,” said Dr Shastri.