Table 1. 2009 Pandemic Influenza A(H1N1) Clinical Attack Rates (% symptomatically infected) and Infection Attack Rates (% infected) in Greece.

Age group	Clinical Attack Rate of Influenza A(H1N1)		Infection Attack Rate of Influenza A(H1N1)
	% (95% CI)		% (95% CI)
	Based on the number ofILI-38a cases	Based on the number of ILI-37b cases
0–4 years	13.1	24.7	36.4
	(7.6–18.6)	(14.1–35.3)	(21.1–51.7)
5–19 years	27.4	53.7	76.2
	(15.5–39.4)	(34.3–73.0)	(43.0–100.0)
20–29 years	7.1	18.1	19.8
	(3.9–10.3)	(11.4–24.8)	(11.0–28.6)
30–49 years	3.1	8.1	8.7
	(1.7–4.5)	(4.8–11.5)	(4.8–12.5)
50–64 years	2.8	7.5	7.6
	(1.4–4.1)	(4.4–10.5)	(3.8–11.5)
65+ years	0.6	2.2	1.6
	(0.2–1.0)	(1.2–3.3)	(0.4–2.8)
Greek population	7.1	15.6	19.7
	(4.8–9.4)	(11.5–19.7)	(13.3–26.1)

Overall and Age-Specific 2009 Pandemic Influenza A(H1N1) Clinical Attack Rates (depending on the definition of influenza-like illness) and Infection Attack Rates (Week 35 of 2009 to Week 6 of 2010).

^aILI-38 : fever >38°C and cough or sore throat, ^bILI-37 : fever 37.1–38°C and cough or sore throat.