The Pune-based Serum Institute of India said on Thursday that it would suspend its clinical trials of the Oxford candidate vaccine against the coronavirus disease, a day after the central drug regulatory authority charged the company of disregarding a global pause.

The international firm AstraZeneca had on Wednesday announced a pause in global clinical trials of the candidate vaccine after an unexplained illness in a vaccine recipient, but Serum Institute had asserted it would continue with the Indian trial, surprising the scientific community.

The Drug Controller General of India had on Wednesday issued a “showcause notice” to Serum Institute, citing AstraZeneca’s decision to suspend clinical trials in Brazil, South Africa, the UK and the US and questioning the world’s largest vaccine maker’s decision to continue the trial in India.

In response to the DCGI’s notice, Serum Institute on Thursday said: “We are reviewing the situation and pausing the India trial till AstraZeneca restarts the trial. We are following the DCGI’s instructions. If the DCGI has any safety concerns, we will follow their instructions and abide by the standard protocols.”

While Serum Institute’s stand on Wednesday had puzzled some scientists, a member of the national task force on Covid-19 had told The Telegraph that it is possible no one was to “immediately” receive the candidate vaccine in the coming days.

In the India arm of the trial, around 100 healthy volunteers would have already received the candidate vaccine and the associated data would be currently under review by the data safety and monitoring board.

It is only after an analysis of this data that more volunteers would receive the vaccine.

“The right thing to be done is to pause trials to understand this,” said Shahid Jameel, a senior virologist and head of the Wellcome Trust DBT India Alliance, a UK-India research partnership.

Around 1,600 healthy volunteers in India are expected to receive the Oxford candidate vaccine at 17 medical colleges across the country.