Italian whole-town study finds 40% of coronavirus cases had no symptoms

FILE PHOTO: Members of the Italian Carabinieri wear face masks as they guard the entrance of the red zone of Casalpusterlengo, closed off due to a coronavirus outbreak in northern Italy, in Casalpusterlengo, Italy, February 26, 2020. REUTERS/Yara Nardi/File Photo

LONDON (Reuters) - A study of coronavirus infections that covered almost everyone in the quarantined north Italian town of Vò found that 40% of cases showed no symptoms - suggesting that asymptomatic cases are important in the spread of the pandemic.

The study, led by a scientist at Italy's Padua University and Imperial College London, also produced evidence that mass testing combined with case isolation and community lockdowns can stop local outbreaks swiftly.