The gap between two doses of the Covishield vaccine should be increased from 28 days to six-to-eight weeks for better results, the Indian central government has asked state governments of the country.
The instruction was given in the middle of round two of nationwide vaccinations, in which people above 60 and those over 45 with other illnesses are being inoculated, reports NDTV.
The revised interval applies only to Serum Institute of India's Covishield - the vaccine developed by Oxford AstraZeneca -- and not to Bharat Biotech's Covaxin, the central government of India said in a letter on Monday.
The previous gap between the two doses was 28 days.
"In view of the emerging scientific evidence, the interval between two doses of a specific COVID-19 vaccine, Covishield, has been revisited by the National Technical Advisory Group on Immunisation (NTAGI) and subsequently by National Expert Group on Vaccine Administration for COVID-19," the letter said.
The centre's letter said it appeared that "protection was enhanced if the second dose of Covishield was administered between six and eight weeks but not later than that.
Covishield and Covaxin have been used in the vaccination drive that rolled out on January 16 with healthcare workers to start with and then frontline workers.
The Health Ministry had earlier said two doses of vaccine needed to be taken 28 days apart to complete the immunisation schedule. The "protective levels of antibodies" were generally developed two weeks after receiving the second dose, the ministry had said.
More than 45.0 million vaccine doses have been given across the country since January.
India has seen a surge in coronavirus cases over the past few weeks, with the daily rise staying above 30,000 since March 18.
India reported 46,951 new coronavirus infections on Monday, a four-month high and the highest so far this year, taking the nationwide COVID-19 tally to 1,16,46,081, according to the central health ministry data.