A leader of the Oxford University group, one of the furthest ahead with human trials, admits the reality is paradoxical, even "bizarre," but said the declining numbers of new infections this summer could be one of the big hurdles vaccine developers face in the global race to beat down the virus.
Even as new cases are growing worldwide, transmission rates are falling in Britain, China and many of the hardest-hit regions in the United States — the three countries that have experimental vaccines ready to move into large-scale human testing in June, July and August.
The shrinking number of new infections in former hot spots is good news, of course. But vaccine developers need sufficient numbers of infected people, with and without symptoms, circulating in the general population — in the streets, workplaces, clinics — to test whether the vaccine protects volunteers when they are exposed.
If there's not much chance of volunteers running into someone with the virus, researchers will have to expand their efforts and potentially chase down outbreaks in other countries, delaying the prospect of a successful vaccine.
Comment: No, actually that still sounds like exploitation, especially if the vaccine comany assumes no liablity for the outcome whatsoever. See also: