Table 4. Comparison of estimated attack rates, ICU admission rates and CFR of 2009 pandemic influenza A(H1N1) with other studies.

Area (Reference)	ClinicalAttack Rate	InfectionAttack Ratef	ICU admission rate (per 100,000 symptomatic cases)	ICU admission rate (per 100,000 infections)	CFR(per 100,000 symptomatic cases)	CFR(per 100,000 infections)
Greece	7.1%–15.6%	19.7%	37.2	13.4	17.5	6.3
Hong-Kong [8] a	-	10.7%*	-	17.6	-	4.4
New Zealand [13]	7.5%	-	-	-	5	-
New Zealand [29]	-	18.3%*	-	-	8.2	4.5
Reunion Island [26]	12.9%	-	23	-	7	-
Singapore [27]	5.4%–11%	-	-	-	6.7	-
UK [9]	-	-	-	-	40	-
UK [31]	-	1.2%–70.2%b*	-	-	-	-
USA [28] c	14%–28%		-	-	10–42	-
USA (New York) [10] d	7.8%–12.2%	-	21–34	-	5–9	-
USA (Milwaukee and New York) [33] e	-	-	28–239	-	7–48	-
France [30]	-	18.1%	-	-	-	-

^aAssessed in individuals 5–59 years old ^bDepending on age and region ^cApril 2009- February 2010 ^dMay–June 2009.

^eApril–July 2009 ^fEstimates denoted with *were obtained by serological surveys.