"His temperature has started coming down and cold and cough is also improving," virologist Atul Patel, one of the five doctors treating Modi, said.
"There is no cause of worry as the health of chief minister has relatively improved and he is responding to treatment," Patel said in a medical bulletin released after examining Modi on Saturday.
According to Patel, the chief minister has been on bed rest since Friday morning.
59-year-old Modi has been kept in isolation at his Gandhinagar residence and has been advised rest for a week. A team of doctors is attending on him round-the-clock.
The BJP leader had complained of cough, fever and body ache on Friday after his return from Russia and tested positive for the virus the same day.
Public functions scheduled to be attended by Modi to mark the birth anniversary of first Home Minister of the country Sardar Vallabhbhai Patel were cancelled on Saturday due to the chief minister's ill health.
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