Ventilation
Three case series from the province Hubei described a high rate of cases who needed ventilation (20%, 23% and 25%) [5,6,10]. German pneumonia patients had a two- to threefold lower ventilation rate of 9%. The two case series from Shenzhen and the province Zhejiang also reported much lower ventilation rates of, respectively, 11% and 2% [9,11] (Figure 2). The median duration of ventilation was 9 days (interquartile range: 7–19, n = 13) for non-invasive and 17 days (interquartile range: 12–19, n = 4) for invasive ventilation in the COVID-19 case series described by Chen et al. [5]. In contrast, the median ventilation duration (invasive and non-invasive) in SPP was only 2 days (interquartile range: 1–4, n = 303). The high ventilation rates and the long duration of ventilation (data from one case series) can be attributed to a high rate of acute respiratory distress syndrome (ARDS) among COVID-19 patients. Again, the difference between Hubei (17–20% ARDS) and outside of Hubei (2–4% ARDS) is striking. However, ARDS was observed in only 1% of SPP.
Figure 2  Reported proportions of patients on ventilation and proportions of patients who were still hospitalised, five COVID-19 case series, China, January–February 2020 (n = 734)
COVID-19: coronavirus disease.
Grey line: proportion of ventilation in pneumonia sentinel patients. Data from five COVID-19 series [5,6,9-11].