The influenza pandemic preparedness planning tool InfluSim

BMC Infectious Diseases

Table 5 Clinical course

	under 20	20 to 59	60 and older
Hospitalized fraction h _{a, r}of untreated severe cases
low risk group (r = r ₁)	0.187%	2.339%	3.560%
high risk group (r = r ₂)	1.333%	2.762%	7.768%
Case fatality d _aof hospitalized cases	5.541%	16.531%	39.505%

Independent of age a and risk group r, a fraction c _{a, r}(A) = 33% of infections result in asymptomatic cases, a fraction c _{a, r}(M) = 33.5% become moderately sick and the remaining fraction develops severe disease. An age- and risk-dependent fraction h _{a, r}of untreated patients with severe disease needs hospitalization. An age-dependent fraction d _aof hospitalized cases dies. Sources: fraction of asymptomatic cases: [11]; 50% of symptomatic cases see a doctor: [9]; hospitalizations per severe case: [9]; case fatality of hospitalized, but untreated patients calculated from [4].

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