As the numbers of COVID-19 cases and deaths in India continue to mount, public health officials are carefully watching yet another looming threat: the appearance of mutations that could be making the virus circulating there more infectious or more capable of causing severe disease.
Scientists believe that the variants of SARS-CoV-2 responsible for this second wave of cases in India already include at least two mutations that make them more dangerous. These mutations are already familiar to COVID-19 experts. One is found in a variant first identified in South Africa, while the other is believed to have emerged from California. Researchers believe that these two mutations may make it easier for the virus to infect human cells and evade the protection provided by immune cells like antibodies. According to the latest data from the public genome database GISAID, 38% of genetically sequenced samples from India collected in March contain the two mutations—scientists have labeled this the B.1.617 variant.
“It’s taken us by surprise,” says Dr. Ravindra Gupta, professor of clinical microbiology at the University of Cambridge who has studied the SARS-CoV-2 virus and its variants, including the one emerging from the UK B.1.1.7. that appears to spread more U.K.sily among people and is now the dominant strain of virus causing new infections in the UK and the US. “The steep, rapid increase U.K.ases is rU. Sly quite startling. It’s probably the result of relaxed social distancing, a lot of social gatherings including religious gatherings, also combined with new variants.”
Sumit Chanda, director of the immunity and pathogens program at Sanford Burnham Prebys Medical Discovery Institute in San Diego, Calif., describes the situation in India as a sort of perfect storm. “People became complacent, and politicians were declaring victory over the virus—a mission accomplished mentality,” he says. “They decided to have one of the biggest religious ceremonies and mass gatherings of humans in the world—I saw pictures, and no one was masked, and it was happening in highly dense population centers. Then you have the emergence of a variant, and that’s what is really driving what is happening over there.”
Chanda says it’s likely that the mutations evolved from the excessive replication among the burgeoning infections in India. With every new person the virus infects, it has a unique opportunity to frantically copy its genome. And in its rush to duplicate its genome, the virus makes mistakes—repeatedly—and those mistakes sometimes end up making the virus fitter and more robust. Those “mistake” versions become variants that start to outcompete and dominate other, less fit viruses.2