COVID-19 | People who were asymptomatic accounted for 86 percent of those who tested positive for Covid-19 in a UK sample population during a lockdown, a study showed on Thursday, meaning the policy of testing people with symptoms might miss many cases.

In England, people are encouraged to get tested for Covid-19 only if they have symptoms of a persistent cough, fever, or loss of taste or smell, with suspected contacts of positive cases told to self-isolate in the first instance...