92. Incidence of Respiratory Syncytial Virus Infection among Hospitalized Adults, 2017–2019

BACKGROUND: Respiratory syncytial virus (RSV) infection has been increasingly recognized as an important cause of acute respiratory illness (ARI) and a trigger for exacerbation of underlying cardiopulmonary disease in adults. Incidence of hospitalized RSV infection remains uncertain as adults have not been systematically screened. Previous incidence estimates, derived primarily from modeling studies, have ranged from 84 to 190/100K population in adults >65 years of age. Accurate burden data are critical to inform RSV vaccine development for adults. We used active surveillance among hospitalized adults to determine population-based incidence rates of RSV infection. METHODS: Hospitalized adults ≥ 18 years old residing in the surveillance area with >2 ARI symptoms or exacerbation of underlying cardiopulmonary disease were screened for eligibility during October 2017–April 2018 and October 2018 to April 2019 in 3 hospitals in Rochester, NY and New York City. Respiratory specimens were tested for RSV using PCR assays. RSV incidence per 100,000 persons (per 2010 US Census data) was adjusted by percent market share for study hospitals in their catchment area. RESULTS: In total, 8,217 hospitalized adults residing in the surveillance area that met the surveillance case definition were tested for RSV; 768 (9.4%) were positive. Adults were aged 18–49 (12%), 50–64 (30%), and ≥65 years old (58%); 55% were female. RSV infection incidence varied from year 1 to year 2 and was highest in patients aged ≥65 years old (table). CONCLUSION: This is the largest prospective RSV incidence study to date. Preliminary results indicate that the incidence of RSV infection may be higher than previously reported, especially in urban-dwelling adults >65 years of age. Results confirm the need for vaccines to prevent RSV infections in older adults. [Image: see text] DISCLOSURES: All Authors: No reported Disclosures.