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There remains limited data on the precise infection ratę and CFR of COVID-19, though a CFR of less than 1% seems likely on the basis of contained outbreaks and studies

As of 10^ May

	Case infection ratę	Death rates	Sample size	Commentary
Diamond Princess	19%	1.8%	3,711	High population of people over 70 compared to average
USS Theodore Roosevelt	21%	0.1%	c.4.6k	Young, physically fit population, so lower mortality ratę than the average expected Heavily skewed towards men, who
Charles de Gaulle	60%	0.0%	1,746	have shown slightly higher mortality rates than women 50-60% of people infected showed no symptoms
Heinsberg, Germany	15%	0.37%	919	c.22% of the patients with positive test had not noticed that they have been infected

•    The Case Fatality Ratę (CFR) of the virus is an important measure to inform the right responses and to enable better accuracy in modelling the virus' spread. It is calculated by dividing the number of cases of infection by the number of deaths of infected people

•    At present there remains limited data to give a precise estimate of the CFR with uncertainty primarily in the true number of cases, but also in the true number of deaths

•    However, large outbreaks in contained environments - such as on board the Diamond Princess cruise ship and the aircraft carriers USS Theodore Roosevelt and Charles de Gaulle - do provide important estimates, even though these are on samples that differ significantly from the average; either morę elderly, as on Diamond Princess, or younger and morę małe as on the aircraft carriers

•    Considering all three of these contained outbreaks together (to give a morę representative population) indicates a CFR of c.0.5% across approximately 10,000 people and over 2,500 cases

•    A smaller but morę representative study in Heinsberg, Germany estimated a CFR of 0.37% across 919 people

•    These studies also provide some indications of the asymptomatic proportion of those infected, with 50-60% of those on the aircraft carriers and 22% of those in the Heinsberg study showing no symptoms. Further research is needed to understand what this means about the accuracy of testing, virus transmission and propensity to fali ill given the presence of the virus

Source: U.S. Navy; Ministere des Armees; Janas Defence; Princess Cruises; Naturę: Verity el al.. The Lancet. April 2020; Office of the Governor of New York; State Government of North Rhine-Westphalia; L.E.K. research and analysis

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