Current as of March 16, 2020 Overall, ~20% of cases are estimated to be severe/critical, requiring significant health capacity for testing and critical-care infrastructure WHO estimated global Context distribution by severity of symptoms WHO estimates ~20% of COVID-19 cases 100% are severe (requiring oxygen) or critical (requiring ventilation) Higher severity has potential to This reflects a higher level of severity overwhelm compared to influenza for instance hospital systems given that these At a country level, mild cases may go Mild 80% cases may require undiagnosed treatment Severe 15% Critical 5% 2020 Source: JAMA, WHO March 6 reports, JAMA, WSJ and associated press interviews with Italian physicians McKinsey and Company 9