Health officials have, for now, ruled out the possibility of a triple mutant avatar of the virus being a factor for the surge in Covid-19 cases in Maharashtra and Mumbai. They have said none of the samples sent to the National Institute of Virology (NIV) and the National Centre for Disease Control (NCDC) have shown a triple mutant variation so far. Without a proper genome sequencing study, one cannot conclude that it is a triple mutant strain which is the cause for the burgeoning cases, doctors and health experts have said.
Recently, the NIV had shared data with laboratories in Maharashtra showing that of the 361 Covid-19 samples from Maharashtra between January and March that were genome-sequenced, 61 per cent, or 220 had the double mutation E484Q+L452R, now classified as being of B.1.617 lineage.
According to McGill University, the triple mutant is a more transmissible variant and is infecting a large number of people within a very short period of time. Scientists believe that the latest global surges are a result of the triple mutation variant in action. Hotspots like Maharashtra, Delhi and West Bengal are considered to be enduring the surge in cases due to this variant. Now that a third mutation in the B.1.617 has been identified, experts are hoping that this time, given the alarm bells ringing all around, the pace of intervention and follow-up picks up.
Doctors from the state’s Covid taskforce said currently, it is speculation as there is no proper evidence of triple mutants being found in Maharashtra or any part of India. So far, they have only come across the double mutant variation and there should be faster genome sequencing to fully understand the triple mutant and how it behaves. “It is a variant of interest now. But the number of samples are from these districts very few and therefore, we cannot directly conclude that the surge is caused by the variant,” said a doctor.
Dr Mangala Gomare, executive health officer,BMC, said they had not come across any samples sent to the NIV or the NCDC showing triple mutant variation; 22 samples had shown the existence of the double mutant. “Every week, we send over 70 samples to the NIV, but so far, no triple mutant strain has been found in any of the samples. We are closely monitoring all the samples sent for the genome sequencing,” she said.
Dr Lancelot Pinto, Consultant Pulmonologist, P D Hinduja Hospital & MRC, said as the pandemic goes on, more mutants are likely to emerge in the future but the way to tackle it remains the same. “Masking, sanitising, and distancing are still the strongest tools against mutants and avoid the three Cs – closed, crowded spaces and close contact with other individuals,” he said.
How the vaccine will impact the mutant is something that initially laboratory studies will tell us, and hopefully, evidence from our own experiences will help us better, according to Dr Pinto. “There is no reason to believe that the current mutant scene in India will escape the immunity offered by existing vaccines,” Dr Pinto added.
City epidemiologists said two of the three variants that combined to form the triple mutant show immune escape responses, making them more resistant to the antibodies. “Even though not much is known about the triple mutant yet, it is believed to have some ability to escape the naturally acquired immunity of the body against Covid-19,”
Health experts said sequencing data, clinical data and epidemiological data must be put together to understand how a mutation will affect. Besides, the need is to continue monitoring the virus evolution. “We know that the South African variant is more capable of escaping immune response. We know that the UK variant is the most transmissible. But we know nothing about the B.1.617 variant. Because we are not putting together data to draw conclusions,” said an official from the Indian Council of Medical Research.