ENGLAND didn’t need a second lockdown because daily covid-19 cases were already peaking under previously imposed regional restrictions, according to a researcher leading a popular symptom-tracking app . “It was unnecessary, if you looked at the latest data on the curves,” says Tim Spector at King’s College London, who oversees the Covid Symptom Study. Other researchers disagree, however.

Almost 3 million people have signed up to the study’s app, which asks users to log how they are feeling each day and input results from any covid-19 tests. …