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asymptomatic for the whole duration of laboratory and clinical monitoring (19 days). Transmission in pre-symptomatic stage of infection: In addition to case reports, pre-symptomatic transmission has been inferred through modelling, and the proportion of pre-symptomatic transmission was estimated to be around 48% and 62% [41]. Pre-symptomatic transmission was deemed likely based on a shorter serial interval of COVID-19 (4.0 to 4.6 days) than the mean incubation period (five days) with the authors indicating that many secondary transmissions would have already occurred at the time when symptomatic cases are detected and isolated [42]. Major uncertainties remain in assessing the influence of pre-symptomatic transmission on the overall transmission dynamics of the pandemic. Vulnerable groups: Population groups that have been more frequently reported having severe disease and death include people above 60 years of age, males, people with underlying conditions such as hypertension, diabetes, cardiovascular disease, chronic respiratory disease and cancer [16,25,28,43,44]. The proportion of most of the reported chronic diseases and health conditions is similar to the prevalence of these conditions in the elderly age groups in China, therefore they might be surrogates of increasing age only. Higher ACE (angiotensin converting enzyme II) gene expression may be linked to higher susceptibility to SARS-CoV-2. It has been shown that ACE 2 expression in lung tissues increases with age, tobacco-use and with some hypertensive treatment. These observations might explain the vulnerability of older people, tobaccousers/smokers and those with hypertension; they also highlight the importance of identifying smokers as a potential vulnerable group for COVID-19 [45-48]. There is limited scientific evidence on the severity of illness among pregnant women with COVID-19. Pregnant women appear to experience similar clinical manifestations as non-pregnant adult patients with COVID-19 pneumonia. There is no evidence of severe adverse outcomes in neonates due to maternal COVID-19 pneumonia, and the virus has not been found in breastmilk [49,50]. Currently available information indicates that children are as likely to be infected as adults, however they experience mild clinical manifestations [34,51]. About 2.4% of the total reported cases in China (as of 20 February 2020) were individuals under 19 years of age. A very small proportion of those aged under 19 years have developed severe (2.5%) or critical disease (0.2%) [16]. Estimates of all of the above parameters are likely to be revised and refined as more information becomes available. There is currently no specific treatment or vaccine against COVID-19 infection, however several clinical trials are recruiting globally to assess the effect of different treatment options and some information in clinical case management is provided under ‘Options for response’. Modelling scenarios related to epidemic peak and health care capacity saturation ECDC estimated the risk of saturation of intensive care unit (ICU) beds and non-ICU beds, as well as hospital isolation capacity (airborne infection isolation rooms and single-bed rooms), through a simulation approach using hospital data of the 2016-2017 ECDC point-prevalence survey of healthcare-associated infections in acute care hospitals [52]. Hospital capacity was evaluated as a function of increasing prevalence of hospitalised COVID-19 cases per 100 000 population, for three levels of hospitalised COVID-19 patients requiring ICU care (5%, 18% and 30% severity scenarios), and using bed occupancy rates measured outside the winter season. The 14-days cumulative notification per 100 000 population was used as a proxy of the prevalence of active COVID-19 cases. Based on these estimates four EU/EEA countries [0 - 10, depending on severity] would have a high risk of seeing their ICU capability saturated at a prevalence of 10 hospitalised COVID-19 cases per 100 000 population (approximately twice the Mainland China prevalence scenario at the peak of the epidemic). At a prevalence of 18 hospitalised cases per 100 000 (the Lombardy scenario as of 5 March) 12 countries [0 – 21, depending on severity] have a high risk of ICU capability becoming saturated. The ICU capacity of all [7 - 28] countries would be exceeded at a prevalence of 100 hospitalised per 100 000 (the Hubei province scenario at the peak of the epidemic) (Annex 2). Nonetheless, despite ICU capacity saturation in most countries, more than half of the countries (17) would still have a residual non-ICU bed capacity in the Hubei scenario. The airborne infection isolation room capacity would be saturated in all countries, well before reaching a prevalence of 10 hospitalised cases per 100 000. In the same prevalence scenario, six countries would not have residual isolation capacity in single rooms either, and no country would have any single room capacity left in a Hubei province scenario. It is important to emphasise that the time needed to reach a saturation situation depends on the size of the country, but that at regional and sub-regional level, hospital systems may be overwhelmed much earlier. According to predictions of the 14-day cumulative notification rate, the majority of EU/EEA countries would reach the Hubei scenario by end of March and all