Previously published estimates of pH1N1 transmission parameters vary by study setting and methods employed. The majority of studies found the mean SI of pH1N1 to range from 2.5-3.3 days [2, [6] [7] [8] [9] [10] [11] ; however, Canada and Texas reported a longer SI of 4-5 days, respectively [12, 13] . Estimates of the R 0 of pandemic influenza from the USA range from 1.3-2.3 [2, 9, 11] . Estimates from Mexico range from 1.4-2.9 [2, 14, 15] . Outside of North America, R 0 estimates include: Australia (mean 2.4) [16] , Canada (mean 2.62) [12] , Thailand (mean 2.07) [17] , Peru (range 1.2-1.7) [18] and New Zealand (mean 1.96) [19] . Finally, Japan revised their mean R 0 estimates from 2.3 to 1.28 after repeating analyses later in the pandemic [20] ; thus demonstrating a need to revisit revised and more complete datasets. A variation in R t with progression of the pandemic was observed in Mexico, averaging at 1.47 (based on a negative binomial model) [14] , but peaking between 2.1-4.0 depending on the generation interval chosen [21] .