Delay in lockdown could have led to threefold jump in coronavirus cases in China

The study found that early detection and isolation of cases was more important than contact reduction and social distancing in the early stages (fivefold versus 2.6-fold) because the focus was quickly preventing more infections.

Early and effective shutdowns are crucial to avoiding a dramatic expansion of the coronavirus disease outbreak, a new study has found, using data to argue that if China had delayed its sweeping restrictions on gatherings and travel by a week, the disease would have affected three times as many patients.

A woman wearing a protective face mask visits the Badaling Great Wall of China after it reopened for business following the new coronavirus outbreak in Beijing, China on Tuesday. (AP Photo)

Using a travel network-based statistical model to simulate the Covid-19 outbreak across mainland China, researchers in the UK, the US and China estimated that if non-pharmaceutical interventions (NPIs) were clamped one week, two weeks, or three weeks later, the number of cases could have shown a threefold, sevenfold, and 18- fold increase across China.

Three major NPIs were considered by the researchers. The first was intercity travel bans; the second was tough screening, contact tracing, identification, diagnosis, isolation and reporting of suspected ill persons; and the third was clamping inner-city travel and contact restrictions to reduce risk of community transmission.

Researchers found that if NPIs had been conducted one week, two weeks, or three weeks earlier in China, cases could have been reduced by 66%, 86%, and 95% respectively, together with significantly reducing the number of affected areas. The geographical range of affected areas would shrink from 308 cities to 192, 130, and 61 cities, respectively.

The study found that early detection and isolation of cases was more important than contact reduction and social distancing in the early stages (fivefold versus 2.6-fold) because the focus was quickly preventing more infections.

But in the longer term, social distancing and contact reduction was crucial in stopping epidemics from increasing. “integrated NPIs would achieve the strongest and most rapid effect on Covid-19 outbreak,” the study found.