1648. Incidence of Norovirus and Rotavirus From Multisite Active Surveillance in Veteran’s Affairs Hospitals, December 2016–February 2018: Results From the SUPERNOVA Network Open Access

Viruses are frequently implicated in acute gastroenteritis (AGE) outbreaks, yet the endemic burden of norovirus and rotavirus disease in adult populations is not well characterized. In 2016, we implemented a multisite AGE surveillance platform capturing cases and controls in 4 VA hospitals (Atlanta, Bronx, Houston, and Los Angeles), collectively serving >320,000 patients annually.

Inpatient AGE cases and age- and time-matched controls were identified through prospective screening of admissions via standardized case definitions. Outpatient cases were passively identified using stool samples submitted for routine clinical microbiological diagnostics. Samples were tested with the FilmArray Gastrointestinal Panel, followed by genotyping of virus positives. Incidence was estimated using population denominators of unique patients served annually by site.

From December 1, 2016 to February 28, 2018, 875 cases (496 inpatients, 379 outpatients), and 374 controls were enrolled. Norovirus and rotavirus prevalence was highest among outpatient AGE cases (11.6% and 2.9%, respectively) followed by inpatient cases (3.4% and 1.6%, respectively); few controls were positive (norovirus, 1.3%; rotavirus, 0%). Norovirus-associated inpatient incidence was 15.2 per 100,000 population (range by site: 10.7–19.9/100,000) and rotavirus-associated inpatient incidence was 7.5 per 100,000 population (range by site: 0–12.8/100,000). The predominant norovirus genotype was GII.P16-GII.4 Sydney (50%), and rotavirus genotype was G12P[8] (83%). Norovirus was detected every calendar month and peaked in December–January, while rotavirus peaked in April. Nine deaths were documented among AGE inpatient cases, including one norovirus-associated death.

Implementation of a multisite AGE surveillance platform captured a wide spectrum of illness for norovirus and rotavirus in US Veterans including outpatient visits, inpatient hospitalizations, and one norovirus-associated death. Norovirus was the leading viral pathogen and was detected year-round. Ongoing surveillance using this platform will allow for further characterization of the pathogen distribution and associated AGE disease burden in adults.

V. Marconi, ViiV: Investigator, Research support and Salary. Bayer: Investigator, Research support. Gilead: Investigator, Research support.