Pandemic influenza in Papua New Guinea: a modelling study comparison with pandemic spread in a developed country

Milne, George J; Baskaran, Pravin; Halder, Nilimesh; Karl, Stephan; Kelso, Joel

General comparative trends may be seen in Table 1 , where we compare the Madang and Albany models. For a pandemic in a developed country setting having a basic reproduction number R0 of 1.5 and an illness attack rate of 31.7%, the same pandemic characteristics applied in a PNG setting with no interventions activated resulted in higher rates of influenza transmission, with an attack rate of 46.6% and reproduction number R0 = 1.88, see Table 1 . Comparing the attack rates when interventions are activated, both intervention strategies (solely school closure and rigorous social distancing) are much less effective in a PNG setting compared to the Australian one. The mitigated illness attack rates in the PNG model are approximately 3 times higher than those in the Australian model with the interventions being 60% -70% less effective. Table 2 indicates where transmission resulting in illness occurred, showing a significantly higher number and proportion (see Table 1 ) of transmissions occurring in households, as opposed to other contact/transmission locations, in PNG compared to the Australian model. The average household size in the PNG model is 2.5 times larger than that in Albany and this had a significant impact on the overall infection rate, making it noticeably higher in the PNG model.