2313. Influenza and Respiratory Syncytial Virus (RSV) Surveillance in the US Department of Veterans Affairs (VA): 2018–2019 Season

BACKGROUND: VA conducts ongoing surveillance for viral respiratory infections, notably influenza and more recently RSV. VA’s large elderly population is at higher risk for influenza and RSV complications, including hospitalization and death. Herein we summarize VA’s 2018–19 national surveillance data. METHODS: Influenza telephone triage, influenza-like-illness (ILI) encounters and antiviral prescriptions plus outpatient visits, laboratory testing (antibody tests excluded), hospitalizations and deaths for both influenza and RSV were obtained from VA data sources (9/30/18–3/31/19) and compared with prior seasons. Influenza vaccinations were captured starting 8/1/2018. Vaccination rates were calculated based on VA users during the fiscal year. RESULTS: Surveillance metrics are presented (Table, Figure). ILI visits ranged from 0.9%-3.3% during the season. RSV peaked earlier than influenza (Week 1 vs. Week 11). Testing revealed 1,674 RSV positives out of 31,404 tests performed (5.3%) and 15,052 influenza positives out of 105,760 tests performed (14.2%). We identified 22 cases of RSV and influenza co-infection (positive test results on the same date or within 3 days). 22% of laboratory-confirmed influenza cases were hospitalized (same proportion as the prior season) while 35% of RSV cases were hospitalized. Median length of stay was longer for RSV hospitalizations (4 days vs. 3 days for influenza). CONCLUSION: The 2018–2019 influenza season was less severe than the 2017–2018 season, and most like the 2016–2017 season. 2018–2019 saw relatively little Influenza B in VA patients, despite elevated activity into the spring. High-dose/adjuvanted vaccine administration increased over the seasons evaluated. RSV surveillance for 2018–2019 demonstrated an earlier peak in activity and the percentage of patients with laboratory-confirmed RSV who were hospitalized and died during their hospitalization was higher compared with influenza. Although fewer RSV tests were performed and testing practices were variable across VA facilities, the weekly trend aligned closely with influenza. Surveillance for both viruses is important in VA given their associated morbidity and mortality. [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.