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

Background Respiratory syncytial virus (RSV) infection causes acute respiratory illness and triggers exacerbations of cardiopulmonary disease. Estimates of RSV incidence in hospitalized adults range widely, and few data exist on incidence in adults with comorbidities that increase the risk of severe disease. 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 ≥18 years residing in the surveillance area with ≥2 ARI symptoms or exacerbation of underlying cardiopulmonary disease were screened for eligibility during the 2017-2018, 2018-2019, and 2019-2020 RSV seasons in three hospital systems in Rochester, NY and New York City. Respiratory specimens were tested for RSV using PCR assays. RSV incidence per 100,000 was adjusted by market share. Results During three winter seasons a combination of active and passive surveillance identified 1,099 adults hospitalized with RSV at three medical centers. Annual incidence during three seasons ranged from 44.2-58.9/100,000. Age-group specific incidence ranged from 7.7-11.9/100,000, 33.5-57.5/100,000, and 136.9-255.6/100,000 in patients 18-49, 50-64, and >65-years of age, respectively. Incidence rates in patients with chronic obstructive pulmonary disease, coronary artery disease, and congestive heart failure were 3-13, 4-7, 4-33 times 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 of RSV hospitalization 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.