Incidence of Respiratory Syncytial Virus Infection Among Hospitalized Adults, 2017-2020

Background: Respiratory syncytial virus (RSV) causes acute respiratory illness (ARI) and triggers exacerbations of cardiopulmonary disease. Estimates of incidence in hospitalized adults range widely, with few data on incidence in adults with comorbidities that increase the risk of severity. We conducted a prospective, population-based, surveillance study to estimate incidence of RSV hospitalization among adults overall and those with specific comorbidities.

Methods: Hospitalized adults aged ≥18 years residing in the surveillance area with ≥2 ARI symptoms or exacerbation of underlying cardiopulmonary disease were screened during the 2017-2018, 2018-2019, and 2019-2020 RSV seasons in 3 hospitals in Rochester, New York and New York City. Respiratory specimens were tested for RSV using polymerase chain reaction assays. RSV incidence per 100 000 was adjusted by market share.

Results: Active and passive surveillance identified 1099 adults hospitalized with RSV. Annual incidence during 3 seasons ranged from 44.2 to 58.9/100 000. Age-group-specific incidence ranged from 7.7 to 11.9/100 000, 33.5 to 57.5/100 000, and 136.9 to 255.6/100 000 in patients ages 18-49, 50-64, and ≥65 years, respectively. Incidence rates in patients with chronic obstructive pulmonary disease, coronary artery disease, and congestive heart failure were 3-13, 4-7, and 4-33 times, respectively, the incidence in patients without these conditions.

Conclusions: We found a high burden of RSV hospitalization in this large prospective study. Notable was the high incidence among older patients and those with cardiac conditions. These data confirm the need for effective vaccines to prevent RSV infection in older and vulnerable adults.