A team of health experts probing Maharashtra’s sharp rise in Covid-19 cases over the past month has hinted at the possibility that mutations could have made the novel coronavirus more infectious but less virulent.

The three-member team said that while pandemic fatigue among the public and laxity in public health responses have likely contributed to the surge in multiple districts, the increase in cases, especially in Amravati, also point to possible mutation.

The team, in a report submitted to the Union health ministry earlier this week, said there is a “possibility of a virus mutation making it more infectious and less virulent.” There is a “sense that the current wave is less virulent,” the report said.

Senior scientists and health researchers, however, cautioned that there is no evidence yet from either genome

sequencing efforts or from mortality data in the public domain that there has been any change in characteristics of the virus circulating in India.

The suggestion being made of a more infectious and less virulent virus is likely based on epidemiological data and some speculation, a senior scientist at one of the 10 national labs involved in genome sequencing the virus told The Telegraph.

“It would be best to wait for more sequencing,” the scientist said. Health officials familiar with the report did not respond to a query from this newspaper asking whether the team’s suggestion about a “less virulent” virus was speculation or backed by epidemiological or sequencing data.

Experts guiding the government’s response to Covid-19 also said they have not yet seen any mortality data displaying a dip in mortality coinciding with the surge in cases that some states have experienced over the past four weeks.

“India’s case fatality rate has consistently been lower than what has been documented in several developed countries,” said Jayaprakash Muliyil, a senior epidemiologist and former professor at the Christian Medical College, Vellore.

Muliyil, relying on a study from Europe on the age-distribution of Covid-19 deaths, had estimated last year that India would experience around 2.2 million deaths during the first year of the pandemic.

“We’re today at around 157,000 – far from what we’d predicted,” Muliyil said. “India’s lower levels of obesity and higher levels of vitamin D may have contributed to keeping mortality low. There may be other factors too.”

Coronavirus genome sequencing efforts in India have detected the presence of what scientists call “variants of interest” because they contain specific mutations that might allow them to evade antibodies or spread easier.

“But as of now, they are not yet variants of public health concern,” a senior health official said. “There is no evidence yet to suggest that the current surge in some states are due to any specific variants.”