Title: Modeling the effects of population structure and vaccination strategy on infectious diseases
Description: We analyze the effects of population structure and vaccination strategy on the spread of infectious diseases among humans. Specifically we consider sexually transmitted diseases (STDs), malaria, and influenza. We argue that STD models that drive health policy should include men who have sex with men by demonstrating that models that include men who have sex with men show markedly different behavior than strictly heterosexual models. We find in some cases that marginal male vaccination is more advantageous than marginal female vaccination in reducing disease prevalence among females. We investigate how male vaccination advantages depend on common STD model parameters. Our sensitivity analysis supports our conclusions and suggests that our model is robust. Recent work recommending that the human papillomavirus (HPV) vaccine be administered only to girls should be reconsidered in light of our findings. We elucidate mathematically the phenomenon whereby a malaria intervention may increase adult human morbidity by decreasing exposure-boosted immunity. We develop a model that, unlike previous work, accurately depicts temporary exposure-boosted immunity to severe malaria, combining discrete- and continuous-time approaches. We find that increased morbidity is technically predicted by all variations within a class of models, but that only some of these variations suggest that increased morbidity is likely to be a major pitfall in intervention planning.

We investigate initial growth rates and critical vaccination levels required to prevent epidemics of susceptible-infective-removed (SIR) diseases such as influenza in populations of households. We analyze reproductive numbers which exhibit divergent behavior in populations of households, though they coincide in homogeneous populations, and observed significant differences between modeling vaccination as a leaky and as an all-or-nothing process. We determine scenarios in which treating household populations as homogeneous populations could lead to insufficient disease control measures.