The highly infectious Delta variant (B.1.617.2) that is believed to have driven the second wave has further mutated to form the Delta plus or ‘AY.1’ variant. Delta-plus 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.
In Maharashtra, it was detected in Ratnagiri in May last week. Since last month, the state 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), Tope said. He said all index cases with this variant will be closely studied. “Their travel history, vaccination status, health condition; and testing of high risk and low risk contacts will be done,” he said. Officials maintained that all those infected in Ratnagiri had mild Covid.
In Mumbai, civic officials were unaware of cases with variants in the city till Tope’s announcement. “We have not been told of these cases yet,” said Suresh Kakani, additional municipal commissioner. Health officials said they will seek information from the state and begin surveillance.
Dr TP Lahane said that in the next three weeks, 100 samples from each district will be sent to laboratories for genome sequencing. “We are also expecting a report of some samples that we had previously sent in the next few days,” he said. At least five more states have reported the presence of Delta-plus.
Dr Rajesh Pandey, principal scientist at CSIR-IGIB, said district authorities must adopt aggressive measures to keep a close watch to guage how it spreads. “A reflection of its infectivity would be, say, if a district that has five cases today ends up with 500 in two weeks,” he said. Delta could infect many in a quick turnaround time. “Whether Delta-plus will behave the same way is not known but looking at the mutation of Delta variant there is all reason to be extra vigilant,” he added.
Diligent contact tracing combined with containment has to be at the heart of efforts to control its spread, Dr Pandey said, adding Delta-plus is a variant of interest at the moment. More studies have to be done to tell whether it has immune escape properties or if it makes a dent on the effectiveness of vaccines.
CSIR-IGIB has signed an MOU with the state to sequence its samples. Following its detection, Dr Pandey said there are plans to increase sequencing from bigger cities like Mumbai, Pune, among others. “How quickly we respond to these findings on ground is one area that has to be focused upon,” he said. The lab now takes around 7-10 days to sequence the samples and communicate the findings to the state.
While Delta-plus was first isolated in Europe in March, authorities in UK found contacts of the first five cases had traveled from or passed through Nepal and Turkey.