The Centre told the Kerala High Court on Thursday that the 84-day gap between two Covishield doses has been prescribed on account of efficacy, Live Law reported.

The central government stated that the gap was increased based on a recommendation by the National Expert Group on Vaccine Administration for Covid-19 for better protection against the disease.

The Centre made the statement in response to a petition by a company named Kitex Garments Ltd, which sought permission to administer the second Covishield dose to its employees before the completion of 84 days from the first dose.

The Union health ministry on May 13 increased the gap between two doses of Astrazeneca’s Covishield vaccine to 12 weeks to 16 weeks from the earlier gap of six to eight weeks.

On August 25, the Kerala High Court had asked the Centre to state whether the 84-day gap was on account of efficacy or availability of the vaccines.

During the hearing, Daya Sindhu Sreehari, the counsel for the central government, told the court that the time interval was based on a scientific study, and that it was necessary for the vaccine’s effectiveness, the Hindustan Times reported.

Justice PB Suresh Kumar has directed the Centre to file a statement on the matter by August 31.

Kitex Garments, in its petition, has stated that it has already inoculated over 5,000 of its workers with the first dose of the vaccine, and has arranged for the second dose as well. The company said that it has not been able to administer the second dose because of the time gap between two doses.

In the previous hearing, the Kerala government told the court that it was following the Centre’s vaccination policy, and unless the Union government changed it, the state could not allow any narrowing of the gap.

Justice Kumar had on Tuesday remarked that if efficacy was the reason for the time interval, then he was “worried”, because he took the second dose within four weeks to six weeks of the first one. He then added that if efficacy was the reason for the policy, then the government should provide scientific data in support of it.

Covishield, which is produced by the Serum Institute of India, was first rolled out when the countrywide Covid-19 inoculation drive began on January 16. The vaccine was developed by pharmaceutical company AstraZeneca and Oxford University.

Three days after India widened the gap between two Covishield doses, the United Kingdom reduced the gap from 12 weeks to 8 weeks for people over 50 years of age, noted the Hindustan Times. The UK reduced the gap citing the threat from the highly transmissible Delta variant of the coronavirus.

In May, data released by Public Health England, the country’s government agency for healthcare, indicates that the protection offered by one dose of the vaccine could be considerably lower than previously thought, especially against the Delta variant.

Till August 27, India has administered 61,22,08,542 Covid-19 vaccine doses in all. In the past 24 hours, 79,48,439 people received coronavirus vaccines, as per the Centre’s data.

India’s Covid vaccination programme has suffered hiccups due to vaccine shortages. Last month, the state governments in Delhi and Odisha announced that several vaccination centres had to remain shut due to the non-availability of Covishield vaccines.