The contribution of testing in the fight against COVID-19: Evidence from Italy.

Background In response to the COVID-19 epidemic a few countries have rolled out widespread testing of the population, while in other countries only people requiring hospital admission are being screened. After an extensive testing strategy during the initial few weeks in the early phase of the epidemic, the Italian Ministry of Health made its testing policy more stringent. In this study we assess the contribution of the testing policy to containing the spread of the COVID-19 epidemic in Northern Italy. Methods The analysis is focused on the evolution of the epidemic and related health intervention in four regions where approximately 80% of the national death toll due to COVID-19 has occurred.The assumed under-estimation of asymptomatic cases has led us to make use of the number of deaths due to the epidemic to analyse the effectiveness of testing. The analysis is conducted through an autoregressive time-series approach where we use official data from the Ministry of Health. Results The results of the analysis confirm a negative relationship between the number of tests carried out and the progression of the epidemic. In particular, results reveal that the tests are particularly effective in breaking the chain of transmission when they are implemented at the early stages of the spread of the virus. Conclusions A large-scale testing policy is recommended as a critical contribution to effectively contain the epidemic. In addition, it is highly recommended to set up all necessary measures to enable the quick scale-up of testing capacity whenever required.