NBC News & The Guardian:
Some scientists are now worried that there won’t be enough ‘wild virus’ cases to properly test a vaccine, nor enough infections to establish herd immunity.
Scientists have warned there could be major delays in producing a Covid-19 vaccine if current UK infection rates remain low and lengthy waiting times are needed to show if candidate products are working. As a result, some researchers insist that ministers must now consider implementing radical alternative measures to speed up vaccine development.
In particular, they argue that Britain should consider deliberately infecting volunteers involved in vaccine-testing projects – in line with World Health Organization proposals to set up such human challenge trials.
In a worrying sign that coronavirus may not be done sweeping through nations that are beginning to emerge from lockdown, recent studies in Spain, France and England indicate that only a small fraction of these countries’ populations had been infected with the virus.
The figure is far lower than the 65 percent of the population many experts believe is needed to achieve so-called “herd immunity” and control the pandemic, the report found.
Herd immunity is when enough people in a population have immunity to an infection to be able to effectively stop that disease from spreading.