New Delhi, May 22 (IANS): Adar Poonawalla, CEO, Serum Institute of India (SII), said on Thursday that developing a vaccine is like a rollercoaster ride with ups and downs.

"Developing a vaccine is like riding a rollercoaster; there are plenty of ups and downs. Sometimes we fail, sometimes we succeed, but we must be patient and not jump to conclusions too early. We must wait for all phase 3 trials to be completed," Poonawalla said in a tweet.

There have been reports that one of the strong candidates for a potential vaccine for Covid-19 being tested by researchers at the Oxord University has failed to protect monkeys from being infected by the virus. However, the potential vaccine helped to protect the monkeys from pneumonia.

Reports of the Oxford vaccine's performance on monkeys had prompted researchers to test the vaccine's potency in humans.

The potential of the vaccine had also led to the Serum Institute announcing plans to manufacture four to five million doses in India. It is one of seven global companies that will manufacture the vaccine being developed by the Oxford Vaccine Group.