Effect of non-pharmaceutical interventions for containing the COVID-19 outbreak in China

Shengjie Lai; Nick W Ruktanonchai; Liangcai Zhou; Olivia Prosper; Wei Luo; Jessica R Floyd; Amy Wesolowski; Mauricio Santillana; Chi Zhang; Xiangjun Du; Hongjie Yu; Andrew J Tatem

As of February 28, 2020 the COVID-19 outbreak has caused 78,961 confirmed cases (2791 deaths) across China, with the majority seen in Wuhan City, and 4691 cases (67 deaths) reported in the other 51 countries. 1 Further spread has occurred to all populated continents of the World, with many anticipating that a pandemic is approaching. 2, 3 As an emerging disease, effective pharmaceutical interventions are not expected to be available for months, 4 and healthcare resources will be limited for treating all cases. Nonpharmaceutical interventions (NPIs) are therefore essential components of the public health response to outbreaks. 1, [5] [6] [7] These include isolating ill persons, contact tracing, quarantine of exposed persons, travel restrictions, school and workplace closures, and cancellation of mass gathering events. [5] [6] [7] These containment measures aim to reduce transmission, thereby delaying the timing and reducing the size of the epidemic peak, buying time for preparations in the healthcare system, and enabling the potential for vaccines and drugs to be used later on. 5 For example, social distancing measures have been effective in past influenza epidemics by curbing human-to-human transmission and reducing morbidity and mortality. [8] [9] [10] Three major NPIs have been taken to mitigate the spread and reduce the outbreak size of COVID-19 across China. 11, 12 First, inter-city travel bans or restrictions have been taken to prevent further seeding the virus during the