Effects of In-Utero Exposure to Seasonal Influenza on Fetal and Infant Outcomes in the United States, 1989-2004

Audrey Dorelien, University of Minnesota

I quantify the impact of seasonal influenza exposure during different gestation months on infant health outcomes. Data comes from the NCHS Birth Cohort Linked- Infant Death Datasets and the Multiple Cause of Death files. My sample consists of 28 million single-births with non-missing information on gestation length from coun- ties with more than 250,000 inhabitants in continental the US. Each observation is linked by conception month to monthly county-level proxy of influenza exposure. I regress individual level health outcomes on monthly-county level influenza mortality rate during different months of gestation while controlling for individual and maternal characteristics. The model estimates the relations between anomalous mortality rates and the different infant health outcomes for a given county and calendar month. I find that influenza exposure has large and statistically significant effects on infant health outcomes; but does not explain most of the variation in infant health outcomes by conception month.