Trigger alert:
More support for the notion that asymptomatic cases are widespread comes from a new report in the British Medical Journal:
"New evidence has emerged from China indicating that the large majority of coronavirus infections do not result in symptoms.
Chinese authorities began publishing daily figures on 1 April on the number of new coronavirus cases that are asymptomatic, with the first day’s figures suggesting that around four in five coronavirus infections caused no illness. Many experts believe that unnoticed, asymptomatic cases of coronavirus infection could be an important source of contagion."
"The latest findings seem to contradict a World Health Organization report in February that was based on covid-19 in China. This suggested that “the proportion of truly asymptomatic infections is unclear but appears to be relatively rare and does not appear to be a major driver of transmission.”
1
But since that WHO report other researchers, including Sergio Romagnani, a professor of clinical immunology at the University of Florence, have said they have evidence that most people infected by the virus do not show symptoms. Romagnani led the research that showed that blanket testing in a completely isolated village of roughly 3000 people in northern Italy saw the number of people with covid-19 symptoms fall by over 90% within 10 days by isolating people who were symptomatic and those who were asymptomatic.
2
Numbers are small, and from China, but consistent with the data from Iceland and the village in Italy that suggests asymptomatic or mildly symptomatic cases are widespread.
Not definitive, but food for thought for those who have already (prematurely in my opinion) closed the books on this issue.
Covid-19: four fifths of cases are asymptomatic, China figures indicate