Risk of influenza after Previous Acute Respiratory Illness in a Cohort of Households with Children


Household studies, sometimes referred to as community or family studies, have contributed immensely to our understanding of acute respiratory illnesses (ARI) from identifying causal agents to estimating vaccine effectiveness. The Household Influenza Vaccine Effectiveness (HIVE) study is an ongoing, prospective cohort study of ARI in households with children in the Ann Arbor, Michigan area. This dissertation uses data from years one (2010-2011) through four (2012-2013) of the HIVE Study to address two topics related to the prevention and spread of respiratory viruses in the household setting. First, there has been substantial research on determinants of influenza vaccine receipt in health care workers and pregnant women, but much less in community dwelling adults and children. We used a theoretical framework based on the Health Belief Model to examine the factors associated with influenza vaccine receipt in adults and their children. We found that not only are factors such as perceived benefits and barriers associated with vaccine uptake, but that many of these factors are modified by external motivators, such as doctor recommendation. Second, a phenomenon that has been termed viral interference has been proposed to explain ecologic trends in viral incidence, particularly with respect to influenza and respiratory syncytial virus (RSV). We used two distinct approaches to determine if there was evidence of viral interference across multiple years of HIVE Study surveillance. The first used an ecologic analysis common in the field of economics to examine trends in viral incidences. In addition, we used an individual based approach to examine the risk of influenza after previous ARI. While trends in viral incidences are correlated, we found little consistent evidence for viral interference, though further work is needed. Collectively, this dissertation highlights the value of a prospective cohort study of ARI in the household setting by illustrating the breadth of topics that can be investigated.