Seasonality and Influenza pH1N12009 Vaccination Impact
The pH1N12009 pandemic exhibited regional variation in pandemic onset, infection dynamics (one, two or three waves) and attack rates. We have developed a two-strain model of influenza infection that tracks seasonal H3N2 and pH1N12009 dynamics over the pandemic timeframe, including vaccination and heterologous cross protection. The model is calibrated using an Approximate Bayesian Computation (ABC) framework using data for seroprevalence, relative subtype dominance and annual attack rates for Australia and the UK. Results show that the pH1N12009 timing and dynamics, and the impact of the 2009 vaccination campaigns, are influenced by the seasonal influenza cycle in these two regions.