Coronavirus screening 'missing more than half of cases': study

Global screening efforts to prevent the rapid spread of coronavirus are likely to fail, according to new research warning that even best-case screenings of air travellers will miss more than half of infected people.

The novel coronavirus has infected more than 80,000 people worldwide since its emergence in central China last month.

Traveller screening using temperature monitors and questionnaires is a key response measure, yet the World Health Organisation (WHO) on Wednesday said for the first time the number of new cases outside mainland China exceeded those within it.

Researchers in the United States and Britain in a study published in the journal eLife used computer models to predict the impact of screening, based on the latest data of how the coronavirus behaves and how long it takes for patients to show symptoms.

Building on similar work in 2015, they found that many cases would inevitably be missed and called for a re-think in how nations screen passengers.

"If someone doesn't realise they have been exposed, and doesn't yet show symptoms, then they are fundamentally undetectable," Katelyn Gostic, a postdoctoral scholar at the University of Chicago and lead author told AFP.

"We estimate that on average, screening will miss about two thirds of infected travellers."
"Some of these people may be true subclinical cases. Others will probably develop symptoms in a few days time. Either way, these stories illustrate the difficulty of screening, where the goal is to detect cases as early as possible, but where people simply don't show detectable symptoms early in the course of infection."