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 ratio in different subpopulations.

Results: The estimated annual incidence of respiratory hospitalizations due to RSV was highest among infants < 1 year of age with low socioeconomic status (2800, 95% CrI [2600, 2900] per 100,000 person-years). We also estimated a considerable incidence in older adults (≥ 65 years of age), ranging from 130 to 960 per 100,000 person-years across different socioeconomic strata. The incidence of hospitalization recorded as being due to RSV represented a significant undercount, particularly in adults. Less than 5% of the estimated RSV hospitalizations were captured for those ≥ 65 years of age.

Conclusions: RSV causes a considerable burden of hospitalization in young children and in older adults in the US, with variation by socioeconomic group. Recorded diagnoses substantially underestimate the incidence of hospitalization due to RSV in older adults.

Fig. 1

Estimated annual RSV-attributable respiratory hospitalization rates by age and SES group, July 2005—June 2014. The color texts show the mean estimates of RSV-attributable respiratory hospitalization rates per year in each age and SES group. The error bars indicate the 95% credible intervals of the estimated RSV-attributable respiratory hospitalization rates. Color blue, yellow, and red correspond to the estimates in populations from low, medium, and high SES ZIP codes, respectively

Fig. 2

Ratio of the number of annual hospitalizations recorded as being due to RSV and the number of estimated annual RSV hospitalizations, by age and SES group, July 2005—June 2014. The size of the circles represents the estimated proportion of hospitalizations caused by RSV that were recorded. The texts show the mean estimates of the recording ratio in each age and SES group. The shaded areas indicate the 95% credible intervals of the reporting ratio. Color blue, yellow, and red correspond to the estimates in populations from low, medium, and high SES ZIP codes

Fig. 3

Monthly respiratory hospitalizations among older adults, July 2005—June 2014. The blue area in the left panel shows the total monthly respiratory hospitalization rate among adults aged 65 and above; the yellow area shows the estimated monthly RSV-associated respiratory hospitalizations in the same age group and the red area shows the hospitalizations recorded as RSV each month. The right panel zooms in to show the increasing trend of recorded RSV diagnoses

Fig. 4

Monthly respiratory hospitalizations in infants < 1 year of age, July 2005—June 2014. The blue area shows the total monthly respiratory hospitalization rate in infants < 1 year of age; the yellow area shows the estimated monthly RSV-associated respiratory hospitalizations in the same age group and the red area shows the hospitalizations recorded as being due to RSV per month