False Positives: Misleading Results or False Narratives?

Bulletin 73 | Matt Fletcher

COVID-19 case numbers in the UK have been increasing significantly in recent weeks. There has been a lot of discussion of whether this increase reflects a real higher rate of infection or a large number of “false positives” (people who are not actually infected testing positive for COVID-19).

Whilst some positive tests will be false positives (and equally some negative tests will be false negatives), based on our understanding of the sensitivity and specificity of COVID-19 tests, we believe that it is highly likely that the vast majority of positive tests represent true positives, and that the testing results fairly represent the level of infectivity in the tested population.