Control and mitigation measures
A wide range of control measures can be considered to contain or mitigate an emerging infection such as 2019-nCoV. Internationally, the past week has seen an increasing number of countries issue travel advisories or outright entry bans on persons from Hubei province or China as a whole, as well as substantial cuts in flights to and from affected areas out of commercial considerations. Evaluation of these mobility restrictions can confirm their potential effectiveness in delaying local epidemics [20], and can also inform when as well as how to lift these restrictions.
If and when local transmission begins in a particular location, a variety of community mitigation measures can be implemented by health authorities to reduce transmission and thus reduce the growth rate of an epidemic, reduce the height of the epidemic peak and the peak demand on healthcare services, as well as reduce the total number of infected persons [21]. A number of social distancing measures have already been implemented in Chinese cities in the past few weeks including school and workplace closures. It should now be an urgent priority to quantify the effects of these measures and specifically whether they can reduce the effective reproductive number below 1, because this will guide the response strategies in other locations. During the 1918/19 influenza pandemic, cities in the United States, which implemented the most aggressive and sustained community measures were the most successful ones in mitigating the impact of that pandemic [22].
Similarly to international travel interventions, local social distancing measures should be assessed for their impact and when they could be safely discontinued, albeit in a coordinated and deliberate manner across China such that recrudescence in the epidemic curve is minimised. Mobile telephony global positioning system (GPS) data and location services data from social media providers such as Baidu and Tencent in China could become the first occasion when these data inform outbreak control in real time.
At the individual level, surgical face masks have often been a particularly visible image from affected cities in China. Face masks are essential components of personal protective equipment in healthcare settings, and should be recommended for ill persons in the community or for those who care for ill persons. However, there is now a shortage of supply of masks in China and elsewhere, and debates are ongoing about their protective value for uninfected persons in the general community.
The Table summarises research gaps to guide the public health response identified.
Table  Research priorities to guide the public health response to 2019-nCoV
Domain  Priorities  Study designs / data sources required
Transmission dynamics  Provide robust estimates of the serial interval and generation time  Detailed exposure and illness onset information from unselected case clusters in line lists, preferably from more than one epicentre
Estimate effective reproductive number (Rt) in other cities (i.e. ex-Wuhan) in China and elsewhere  Epidemic curves for each city by dates of illness onset, preferably stratified by likely source of infection (zoonotic, environmental point source, local case vs imported index case)
Clarify the relative importance of pre-symptomatic / asymptomatic transmission  Detailed reports of transmission events and symptomatic status of infectors; viral shedding data; special studies in households and other closed settings
Determine the role of different age groups in transmission, particularly children  Transmission studies in households and other closed settings; serological studies
Determine the relative importance of possible modes of transmission  Outbreak investigations, in particular for superspreading events; environmental sampling, air sampling and exhaled breath sampling; special studies in households and other closed settings
Determine environmental effects on virus survival and transmission  Virus survival studies in situ vivo and in vitro; environmental sampling studies
Severity  Provide robust estimates of the risk of fatality of hospitalised cases, by age or other important groupings  Reports from unselected clinical cohorts of times to death or recovery among resolved cases
Provide robust estimates of the risk of fatality of symptomatic cases, by age or other important groupings  Estimates of incidence from population-wide surveillance of mild cases
Identify groups at high risk of severe infection  Case–control studies; cohort studies
Susceptibility  Determine if children are infected, and if so, if they are infectious  Transmission studies in households and other closed settings; serological studies
Determine if all infections result in neutralising immunity  Convalescent serology from mild as well as severe cases, in all age groups
Control measures  Provide impact estimates of travel restrictions, border screening and quarantine policies on non-local spread  Modelling analyses of local and global spread of infections
Estimate the effects of social distancing measures and other non-pharmaceutical interventions on transmissibility  Comparative analyses of transmissibility in different locations
Predict the most effective measures to reduce the peak burden on healthcare providers and other societal functions  Modelling studies incorporating healthcare capacity and processes In conclusion, there are a number of urgent research priorities to inform the public health response to the global spread of 2019-nCoV infections. Establishing robust estimates of the clinical severity of infections is probably the most pressing, because flattening out the surge in hospital admissions would be essential if there is a danger of hospitals becoming overwhelmed with patients who require inpatient care, not only for those infected with 2019-nCoV but also for urgent acute care of patients with other conditions including those scheduled for procedures and operations. In addressing the research gaps identified here, there is a need for strong collaboration of a competent corps of epidemiological scientists and public health workers who have the flexibility to cope with the surge capacity required, as well as support from laboratories that can deliver on the ever rising demand for diagnostic tests for 2019-nCoV and related sequelae. The readiness survey by Reusken et al. in this issue of Eurosurveillance testifies to the rapid response and capabilities of laboratories across Europe should the outbreak originating in Wuhan reach this continent [23].
In the medium term, we look towards the identification of efficacious pharmaceutical agents to prevent and treat what may likely become an endemic infection globally. Beyond the first year, one interesting possibility in the longer term, perhaps borne of wishful hope, is that after the first few epidemic waves, the subsequent endemic re-infections could be of milder severity. Particularly if children are being infected and are developing immunity hereafter, 2019-nCoV could optimistically become the fifth human coronavirus causing the common cold.