Coronavirus UK: Contract tracing may mean 770k self-isolate a day

London School of Hygiene and Tropical Medicine (LSHTM) made the estimate. They say for every 20,000 new cases each day, 770,000 people would be traced. Currently 3,000 cases are diagnosed per day but it is heavily under-reported. The study measured the impact of app-based tracing against manual tracing . Both methods are due to be implemented by health chiefs in the coming weeks.