"Since the high court has given a judgement, it will have to be done," said one of the sources. "For the government's programme, the ideal gap remains 12 weeks."
India doubled the gap between the AstraZeneca vaccine's two doses in May to make sure more people were inoculated with at least one dose when supplies were scarce at the height of the country's outbreak this year.
AstraZeneca recommends the second dose of its COVID-19 vaccine be taken four weeks after the first shot, but says on its website there is a "trend of increased efficacy with a longer than 4 week dosing interval". The World Health Organization recommends an interval of eight to 12 weeks.