pilot city-wide covid-19 testing
Coronavirus: Liverpool to pilot city-wide Covid-19 testing
False positives - when you don't have the virus, but the test says you do - are also a bigger problem when you test large numbers of people. One analysis suggested a twice-a-week test for six months using a test with a 1% false positive rate would lead to more than 40% of people being wrongly told they had the virus.