Guwahati,  Amid the rising number of Covid-19 cases in Assam, samples of the double mutant variant of novel coronavirus have been found at the Dibrugarh Airport, the first such detection in the northeastern region, officials said on Friday.

Health officials said that before Assam, the double mutant strain was founda in Maharashtra, Delhi and West Bengal.

Assam Health Minister Himanta Biswa Sarma tweeted: "Recent samples from Dibrugarh Airport are positive for B.1.617 strain or the Indian double mutant (L452R and E484Q) strain of SARS-Cov-2. We need to be very very careful."

The double mutant (B.1.617) strain is said to be responsible for the current surge in Covid-19 cases in Maharashtra and few other states in India.

Scientists had earlier feared that vaccines may not offer protection against the double mutant strain as it may escape the immune system.

"There were 7,685 active cases in Assam on Tuesday night and it rose to 10,571 late on Thursday night. So far, 2,31,069 positive cases have been reported from across the state, while 1,160 patients have succumbed to the virus," a health official said.