Interactions between immunization strategies and pandemic influenza associated severe outcomes
The effect of multiple pandemic waves on morbidity as quantified by the number of intensive care unit admissions is investigated. A seasonal morbidity function based on probability data from the H1N1 pandemic of 2009 is used and compared to the most common approach used in current literature. We find pandemic scenarios where due to vaccination, a second wave in winter, spring or summer can have a higher number of intensive care unit (ICU) admissions overall even though vaccination is successful in reducing the number of infections in total. This occurs because of additional susceptibility available in winter due to vaccination in the fall. We also find that predicted estimates of ICU cases differ significantly on how the data on severe outcomes from a pandemic is modeled - whether the probability of an ICU admission is held constant or modeled as a seasonally varying function.