The global search for a coronavirus vaccine has a “very high chance of success”, the London scientist leading one of two UK bids said today.

Professor Robin Shattock, of Imperial College London, said the scientific community was “very confident” that a jab able to prevent people contracting the virus could be developed.

His assessment is the most upbeat yet and comes after fears that a vaccine — the key to ending the death toll from Covid-19 — could take 12 to 18 months to discover and mass produce.

The Imperial team today appealed for healthy volunteers to enrol in its trials that will begin in June.

The U.K. will begin human trials of a coronavirus vaccine Thursday, Health Secretary Matt Hancock said, as he argued that the government’s strategy for fighting the disease had succeeded.

“In the long run, the best way to defeat coronavirus is through a vaccine,” Hancock told the government’s daily news conference. “The U.K. is at the front of the global effort. We have put more money than any other country into a global search for a vaccine and, for all the efforts around the world, two of the leading vaccine developments are taking place here at home.”

The trials will be of a drug developed at Oxford University. Hancock said the government would give 20 million pounds ($25 million) to support the research. “In normal times, reaching this stage would take years,” he said. Another 20.5 million pounds will go to a separate project at London’s Imperial College.

Hancock was trying to show progress as the government faces criticism over shortages of protective medical equipment. He was speaking on the day that the Office for National Statistics released data showing the dramatic toll of the virus. It said that in the week ending April 10, 18,516 deaths had been registered, the highest weekly number in more than two decades and 76% more than the average for that week.

Complaints from health workers about the availability of personal protective equipment continue, but Hancock was keen to emphasize the government’s achievements. He said that with the number of people hospitalized with the virus declining, the ministers had achieved their goal of protecting the National Health Service from being overwhelmed.