Mutations make coronavirus infectious: Experts

In mid-February, the positivity rate in Amravati and Yavatmal reached 50% and 32% and genome sequencing showed the presence of two mutations (E484Q and N440K)

The Central government confirmed on Wednesday that a “double mutation” of the virus that causes Covid-19 has been found in Maharashtra. Experts believe it is responsible for the 17% spike in Covid-19 cases in Maharashtra. They have observed that the variant in Maharashtra appears to be more transmissible, but less virulent.

Mutations make coronavirus infectious: Experts

In mid-February, the positivity rate in Amravati and Yavatmal reached 50% and 32% and genome sequencing showed the presence of two mutations (E484Q and N440K). The state sent 900 samples — 223 from Mumbai — from Covid hot spots and of travellers and families for analysis. While studying them, a new variant was found.

In a statement on Wednesday, the Centre said, “The analysis of samples from Maharashtra has revealed that compared to December 2020, there has been an increase in the fraction of samples with the E484Q and L452R mutations...these mutations have been found in about 15-20% of samples and don’t match any previously categorised variants of concerns.”

E484Q and L452R have been categorised as escape mutations. Epidemiologist Dr Lancelot Pinto said escape mutations make the virus more infectious. “Variants are expected to evolve when a highly transmissible virus moves rapidly through a host population. Such new variants of the coronavirus could have escape mutations which help the virus evade the body’s immune system, thereby conferring the virus with a survival advantage. Escape mutations in the spike protein could result in infections among individuals who had existing antibodies to earlier strains of the virus,” said Dr Pinto. Epidemiologists believe the mutation has contributed to the spike in Maharashtra’s caseload. “An analysis of the trend of the infection spread in the state had indicated a mutation months ago. Like mutation trends in other countries like the UK and South Africa, it was spreading faster and patients from same families were contracting the infection,” said Dr Subhash Salunke, state advisor for Covid-19.

Dr Rahul Pandit, part of the state’s Covid task force, said the mutated viruses are more contagious but most patients are either asymptomatic or mildly symptomatic. “Unlike the first strain, this one is less virulent. But we have to wait and watch. We are also concerned that there is a possibility that it can turn more deadly and the severity may increase,” he said. Dr Pandit also said it may be possible for recovered patients to be reinfected by the new strains. Experts say it is too soon to know how effective Covishield and Covaxin are against the mutations. “The Astra Zeneca vaccine had a lower efficacy among individuals infected with the South African variant. Whether the vaccine will be effective against infections with the newer variants needs to be studied, first with in-vitro experiments in the lab, and then in clinical trials to assess efficacy among subjects who receive the vaccine,” Dr Pinto said.