Table 1.

Parameter Combinations for the 10 Best-Fit Susceptible-Infected-Recovered Susceptible Simulations at the Arizona, Florida, Illinois, New York, and Washington State Sites^a,^b

Ordered Model Rank	L, Years	D, Days	R0max, Persons/Person	R0min, Persons/Person
1	5.35	3.24	3.52	1.12
2	5.40	2.41	2.89	1.16
3	3.28	4.18	3.40	1.22
4	3.70	2.03	2.05	1.15
5	7.77	2.59	3.69	1.30
6	6.23	2.37	2.71	1.23
7	6.05	2.56	3.79	1.06
8	4.61	2.71	2.61	1.29
9	7.39	2.85	3.69	1.27
10	3.58	3.61	3.19	1.20

Abbreviations: R_0max, a constant that defines the maximum basic reproductive number, R₀(t), at zero absolute humidity; R_0min, a constant that defines a baseline level for basic reproduction number, R₀(t), at high absolute humidity; RMS, root mean square; SIRS, susceptible-infected-recovered susceptible.

^aAdapted from Shaman et al. (2).

^bAt each site, 5,000 simulations were performed with the parameters R_0max, R_0min, D (mean infection period), and L (mean duration of immunity) randomly chosen from within specified ranges. Best-fit SIRS simulations were selected for the 5 sites in aggregate based on RMS error after scaling the 31-year mean daily infection number to the 31-year mean observed daily excess pneumonia and influenza mortality rate at each site.