Estimated Incidence of Respiratory Hospitalizations Attributable to RSV Infections across Age and Socioeconomic Groups

Abstract Background Surveillance for respiratory syncytial virus (RSV) likely captures just a fraction of the burden of disease. Understanding the burden of hospitalizations and disparities between populations can help to inform upcoming RSV vaccine programs and to improve surveillance. Methods We obtained monthly age-, ZIP code- and cause-specific hospitalizations in New York, New Jersey, and Washington from the US State Inpatient Databases (2005-2014). We estimated the incidence of respiratory hospitalizations attributable to RSV by age and by socioeconomic status using regression models. We compared the estimated incidence and the recorded incidence (based on ICD9-CM) of RSV hospitalizations to estimate the under-recorded rate in the different sub-populations. Results The estimated annual incidence of respiratory hospitalizations due to RSV was highest among infants <1 year of age with low socioeconomic status, (2700 per 100,000 people, 95% CrI 2600, 2900) and were considerable in older adults that are ≥65 years of age across socioeconomic status, ranging from 130 to 970 per 100,000 people. The incidence of hospitalization recorded as being due to RSV represented a significant undercount, particularly in adults. Only <5% of the estimated RSV hospitalizations were captured for the older adults that are ≥65 years of age. Conclusions RSV causes a considerable burden of hospitalization in young children and in older adults in the U.S, with variation by socioeconomic group. Estimates of the incidence of hospitalizations due to RSV in older adults based on the recorded diagnoses likely represent an underestimate. Key messages What is already known on this topic? Previous study suggested that the incidence of hospitalization for bronchiolitis (often caused by RSV) in infants varies greatly between communities of different socioeconomic levels. However, it is unclear whether these differences are associated with the admission criteria or the risk of RSV infection. What this study adds? The estimated annual incidence of respiratory hospitalizations due to RSV in infants residing in low socioeconomic areas was about twice as high as the incidence in infants residing in high socioeconomic areas. In older adults, a small fraction of the hospitalizations estimated to be caused by RSV were recorded as such in the inpatient database. How this study might affect research, practice or policy? With several vaccines and extended half-life monoclonal antibodies against RSV under active development, these estimates can help anticipate the impact of RSV prevention strategies in populations of different demographic characteristics.