The government on Tuesday said it had found no reason to stop Oxford vaccine trials in India after reviewing a Chennai volunteer's allegation of serious adverse effects, including memory loss and change in behaviour.

The Adar Poonawalla-led Serum Institute of India (SII) also said the vaccine was "safe and immunogenic" and the Data and Safety Monitoring Board and the Ethics Committee had "independently cleared" the trials after examining the complaint.

''After initial causality assessment, findings did not necessitate stoppage of the Serum trials. SII vaccine trials have entered Phase 3. After reviewing all documents, SII has been given permission to conduct Phase 3 trials. Bharat Biotech also has been allowed to conduct Phase 3 trials," said Rajesh Bhushan, Health Secretary.

The Serum Institute defended its 100-crore defamation notice to the Chennai volunteer, saying it wanted to "safeguard the reputation of the company which is being unfairly maligned."

The wife of the volunteer said since he received a trial dose, he had lost an American project and had found it difficult to even make simple online payments. She also denied there was any motive, financial or otherwise, in their legal notice to the vaccine-maker in November. The family has claimed ₹ 5 crore as compensation.

The 40-year-old marketing professional was a volunteer for the third phase of the Covid vaccine trial and was administered a dose on October 1.

"Our primary demand was to bring this to the notice of people. This vaccine is being called the option for India. We can't stay quiet. We could have sold our silence, we could have just sent a notice and gained something... But our hearts wouldn't let us do that," the woman told NDTV on phone from Chennai.

She described her husband as a well-informed, creative person. "His ability to write, present things in a creative manner were his plus points. Now he is unable to do his work," she said, adding that though he was better, he still faced problems doing simple tasks