The world’s first “human challenge” trial in which volunteers were deliberately exposed to the coronavirus has found that symptoms had no effect on how likely an infected person is to pass the disease on to others. The findings underscore the difficulty in preventing community infections as the Word Health Organization (WHO) warns of a rise in cases.

The research project, run by Open Orphan (ORPH.L) with Imperial College, London, showed that among the 18 participants that caught COVID-19, the severity of symptoms, or whether they developed symptoms at all, had nothing to do with the viral load in their airways. The viral load, or tendency to shed the virus, was measured by two methods known as focus-forming assay (FFA) and quantitative polymerase chain reaction (qPCR). Read more here.