The Indian government doubled the amount of time required between doses of AstraZeneca’s Chinese coronavirus vaccine in the country without the agreement of a scientific group it claimed had greenlighted the action, Reuters reported Tuesday.

India’s Ministry of Health and Family Welfare announced May 13 it would extend the time period between AstraZeneca doses from 6-8 weeks to 12-16 weeks. The ministry said the gap extension was recommended by the National Technical Advisory Group on Immunisation (NTAGI) in India. Three NTAGI members told Reuters in a report published June 15 that the advisory group did not approve an extension gap for AstraZeneca beyond 12 weeks.

“M.D. Gupte, a former director of the [Indian] state-run National Institute of Epidemiology, said the NTAGI had backed increasing the dosing interval to 8-12 weeks — the gap advised by the World Health Organization. But he added that the group had no data concerning the effects of a gap beyond 12 weeks,” according to Reuters.

“Eight to 12 weeks is something we all accepted, 12 to 16 weeks is something the government has come out with,” Gupte told the news agency. “This may be alright, may not be. We have no information on that.”

“This was echoed by his NTAGI colleague Mathew Varghese, who said the group’s recommendation was only for 8-12 weeks,” Reuters reported.

“J.P. Muliyil, a member of the seven-strong COVID working group, said there had been discussions within the NTAGI on increasing the vaccine dosage interval but that the body had not recommended 12-16 weeks,” according to the news agency.

“That specific number was not quoted,” he told Reuters, without elaborating.

AstraZeneca is a British-Swedish multinational pharmaceutical company headquartered in England. Together with Oxford University, AstraZeneca developed a Chinese coronavirus vaccine known in India as “Covishield.” The product “accounts for nearly 90 percent of the 257.5 million [Chinese coronavirus] vaccine doses administered in India,” according to Reuters. The Serum Institute of India manufactures Covishield within India.

When announcing its new gap extension between AstraZeneca doses on May 13, India’s health ministry said it had based the decision, in part, on real-life evidence from Britain, without providing further detail.

“The COVID Working Group chaired by Dr N K Arora has recommended extension of the gap between the first and second doses of COVISHIELD vaccine to 12-16 weeks. The present gap between the two doses of COVISHIELD vaccine is 6-8 weeks,” India’s Ministry of Health and Family Welfare announced in a press release.

“Based on the available real-life evidences, particularly from UK, the COVID-19 Working Group agreed for increasing the dosing interval to 12-16 weeks between two doses of COVISHIELD vaccine,” the ministry wrote.

AstraZeneca’s Covishield vaccine “is made from a weakened version of a common cold virus (known as an adenovirus) from chimpanzees. It has been modified to look more like coronavirus — although it can’t cause illness,” the BBC reported June 16.

“When the vaccine is injected into a patient, it prompts the immune system to start making antibodies and primes it to attack any coronavirus infection,” according to the British broadcaster.

“The jab is administered in two doses given between four and 12 weeks apart. It can be safely stored at temperatures of 2C [35.6 degrees Fahrenheit] to 8C [46.4 degrees Fahrenheit] and can easily be delivered in existing health care settings,” according to the BBC.