Influenza Hospitalizations And Census Tract Ses In Ct 2013-2018

Nicole Elizabeth Torigian

This thesis is restricted to Yale network users only. It will be made publicly available on 08/28/2021


Background: Influenza hospitalizations are a costly outcome of influenza infection. Socioeconomic status (SES) is not typically collected through routine public health surveillance methods, but understanding SES allows for targeted interventions.

Methods: Surveillance data from the CT Emerging Infections Program’s US Influenza Hospitalization Surveillance Network (FluSurv-Net) component was used to identify cases of laboratory confirmed influenza-associated hospitalizations in the 5 influenza seasons from 2013-2018. Case-patient home addresses were geocoded and linked to census tract level factors from the U.S. Census Bureau. Both census tract level poverty and crowding were broken into 4 categories: low, medium low, medium high, and high. Trends by decreasing SES category were measured by chi square for trend; incidence rate ratios (IRR) of the lowest to highest SES group were used to measure the magnitude of any trend associations found. Results: Decreasing SES was significantly (p<0.05 for trend) associated with increasing influenza-associated hospitalization incidence for both census tract level poverty and crowding. The findings were stronger for poverty than for crowding (IRR 2.39 vs 1.39). Poverty findings were consistent across characteristics examined with one exception: 0-4 year olds, where the association was not significant. Compared to previous studies, the magnitude of the association with poverty decreased (IRR for children <18 years: 2.21 vs 3.64; and for adults: 2.48 vs 2.96).

Conclusions: The previously described association between higher census tract level poverty and crowding and higher influenza-associated hospitalization incidence has decreased, particularly in young children. This may be due in part to changing access to healthcare, new daycare vaccine requirements, enhanced awareness following previous studies, and changes in influenza screening practices at hospitals. Continued efforts to reduce this disparity are needed.