LONDON/ZURICH (BLOOMBERG, REUTERS) - The Oxford University team in charge of developing a coronavirus vaccine said a decline in the infection rate will make it increasingly difficult to prove whether it has been successful, the Telegraph reported.
"It's a race against the virus disappearing, and against time," Professor Adrian Hill, director of the university's Jenner Institute, told the newspaper.
"We said earlier in the year that there was an 80 per cent chance of developing an effective vaccine by September. But at the moment, there's a 50 per cent chance that we get no result at all."
Prof Hill said he expects fewer than 50 of the 10,000 people who have volunteered to test the vaccine trial in coming week to catch the virus. If fewer than 20 test positive, the results may be useless, the newspaper cited him as saying.
Although developers globally are working on as many as 100 experimental vaccines for Covid-19, the process is likely to take time.
Finding a vaccine and distributing it globally will be a "massive moonshot", Dr Michael Ryan, executive of director of the World Health Organisation's Emergency Programme, said earlier this month. There's a chance the disease may be here to stay, he said.
The British government has agreed to pay for as many as 100 million doses, adding that 30 million may be ready by September. The daily rate of new infections has fallen by almost two thirds since hitting a peak of almost 9,000 on April 10.
Separately, Reuters reported that Oxford University may join Moderna in a large-scale testing programme in July.
Long road ahead
Meanwhile, the head of the Gavi vaccine alliance said the first indications of the effectiveness of a potential vaccine against coronavirus may be available in the autumn, forecasting a long road from there to broad availability.
"Unfortunately, we really do not know which vaccine will work and whether there will be one at all. If we're lucky, we'll receive indications in autumn as to (a potential vaccine's) effectiveness," Gavi head Seth Berkley told Swiss newspaper NZZ am Sonntag in an interview published on Sunday (May 24).
"But there will still be a long way to go from there until an approved active substance becomes available in large quantities for the global population."
Calling for globally coordinated efforts both to produce and share an eventual vaccine, Dr Berkley said international agreement was needed to build up manufacturing capacity to rapidly produce a vaccine once one is found.
"(Countries) should work together in order to share in each other's vaccines in case one's own are not good," he said, adding it was possible some vaccines would work better for younger people and others for older age groups.
He urged the WHO to issue clear guidelines on a vaccine's use and distribution to prevent a vaccine first being made available to the rich at the expense of the people most in need.
Should an effective vaccine become available in an initially limited supply, it should first be used to immunise health personnel, he said.