Table 2.

Simulated Pandemic Influenza A (H1N1) Illness Attack Rates and Numbers of Cases, Hospitalizations, and Deaths for Los Angeles County and the Continental United States in 3 Scenarios^a

Measure and Scenario	Los Angeles Countyb									Continental United Statesc
	Childrend			Adultsd			Total			Children			Adults			Total
	%	Mean	Range	%	Mean	Range	%	Mean	Range	%	Mean	Range	%	Mean	Range	%	Mean	Range
Illness attack rate
No vaccination	36.2			15.4			21.4			35.6			15.8			21.5
Vaccination	32.2			13.0			18.5			31.1			13.4			18.5
Early vaccination	23.9			9.4			13.5			23.8			10.0			14.0
No. of cases
No vaccination		1.15M	0.82M–1.69M		1.22M	0.87M–1.79M		2.37M	1.69M–3.48M		27.9M	19.9M–41.0M		36.0M	25.6M–52.8M		63.9M	45.5M–93.8M
Vaccination		1.02M	0.73M–1.50M		1.03M	0.73M–1.51M		2.05M	1.46M–3.02M		24.4M	17.4M–35.8M		30.7M	21.8M–45.1M		55.1M	39.2M–80.9M
Early vaccination		0.76M	0.54M–1.12M		0.74M	0.53M–1.09M		1.50M	1.07M–2.21M		18.7M	13.3M–27.4M		22.8M	16.2M–33.5M		41.5M	29.5M–60.9M
CDC estimatese											19.5M	13.9M–28.6M		41.3M	29.4M–60.7M		60.8M	43.3M–89.3M
No. of deaths
No vaccination		68	48–100		338	240–496		406	289–596		1,790	1,270–2,630		10,200	7,260–15,000		12,000	8,540–17,600
Vaccination		56	40–82		266	189–391		322	229–473		1,540	1,090–2,260		8,610	6,120–12,600		10,100	7,220–14,900
Early vaccination		38	27–56		177	126–260		215	153–316		1,160	821–1,700		6,280	4,460–9,210		7,430	5,280–10,900
CDC estimates											1,280	912–1,880		11,200	7,960–16,400		12,500	8,870–18,300
No. of hospitalizations
No vaccination		4,690	3,340–6,890		5,640	4,010–8,280		10,300	7,350–15,200		0.12M	0.09M–0.18M		0.17M	0.12M–0.25M		0.29M	0.21M–0.43M
Vaccination		3,810	2,710–5,600		4,450	3,170–6,540		8,270	5,880–12,100		0.11M	0.07M–0.15M		0.14M	0.10M–0.21M		0.25M	0.18M–0.37M
Early vaccination		2,630	1,870–3,870		2,970	2,110–4,350		5,600	3,980–8,220		0.08M	0.06M–0.12M		0.11M	0.07M–0.15M		0.18M	0.13M–0.27M
CDC estimates											0.09M	0.06M–0.13M		0.19M	0.13M–0.28M		0.27M	0.20M–0.40M

Abbreviations: CDC, Centers for Disease Control and Prevention; M, million.

^aThe 3 scenarios were: baseline (no vaccination), vaccination (vaccination begins in early October), and early vaccination (vaccination begins in early September).

^bResults for Los Angeles County are averages from 5 runs.

^cResults for the United States are from a single stochastic run from simulations based on the 2000 US Census (http://www.census.gov/geo/www/cenpop/tract/tract_pop.txt), adjusted to the 2009 US population.

^dChildren were defined as persons aged 18 years or younger, while adults were those aged 19 years or older.

^eEstimates for the United States were obtained from the CDC (3).