The easing of Covid restrictions over the past week has happened almost as quickly as the abrupt measures to lock down cities at the beginning of the pandemic. At first I was sceptical and thought the situation would only go back to how it was in the second half of 2020, when China stayed mostly clear of infections with only mild restrictions in place, even though the rest of the world was being bombarded by the virus. But almost immediately: we are no longer required to show our health code and negative Covid results upon entry to public venues; health...