Symptomless cases in schools could be key driver in spread of Covid-19

Up to 70% of schoolchildren infected with coronavirus may not know they have it until after a positive test result

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A key factor in the spread of Covid-19 in schools is symptomless cases. Most scientists believe that between 30% and 40% of adults do not display any Covid symptoms on the day of testing, even if they have been infected. For children, however, this figure is higher.

It is probably more like 50% for those in secondary school while for boys and girls in primary school, around 70% may not be displaying symptoms even though they have picked up the virus," says Professor Martin Hibberd of the London School of Hygiene and Tropical Medicine.