Estimating the Case Fatality Risk of COVID-19 using Cases from Outside China

Nick Wilson; Amanda Kvalsvig; Lucy Telfar Barnard; Michael Baker

Based on a news report on 13 February [8] : "Kato said five people from the ship are currently in serious condition in hospital". A prior report on 12 February in the same news source gave more detail for the first four people where the Health Minister (Katsunobu Kato) was reported saying: "At this point, we have confirmed that four people, among those who are hospitalised, are in a serious condition, either on a ventilator or in an intensive care unit." [9] Total 4.0% (14/349) Next we considered the typical survival of people admitted to ICUs with severe respiratory conditions. We used data from a meta-analysis of trials comparing higher vs lower levels of positive end-expiratory pressure (PEEP) in adults with acute lung injury or acute respiratory distress syndrome (ARDS) [10] . This study found 374 hospital deaths in 1136 patients (32.9%) assigned to treatment with higher PEEP and 409 hospital deaths in 1163 patients (35.2%) assigned to lower PEEP (with no significant difference between these two groups). Combining these data suggests a CFR in such patients with acute lung injury of 34.1% (783/2299). This estimate is a little less than one case series of ICU patients with acute respiratory failure from Influenza A (H1N1) and requiring mechanical ventilation, who had a CFR of 46% (156/337) [11] . Another study of such ICU patients with influenza found a lower overall CFR of 26% (492/1859) [12] and another one reported a CFR of 24% (177/733) [13] . Furthermore, in a group of 340 ICU patients with ARDS, the CFR at 90 days was 32% in a group given a neuromuscular blocker and 41% in the placebo group [14] .