Reviewed by Sanchi Malhotra MD, University of California Los Angeles
The authors from a pediatric hospital describe a Norovirus outbreak on their ICU step-down unit in February 2024. The index patient had been admitted for 3 months prior to infection, with an unclear source, though community transmission of norovirus had been increased. The outbreak went on to affect 8 other patients with an attack rate of 38%, all who had been already hospitalized >72 hours. 15 employees were affected, with epidemiologic links within 48 hours of gastroenteritis symptom onset. Mitigation efforts included increased frequency of surface cleaning from once to 3 times daily, ultraviolet cleaning of the common spaces, hydrogen peroxide vapor cleaning in rooms that had infected patients, unit-wide contact precautions and soap and water hand hygiene requirement, and implementation of 72-hour furlough for staff after resolution of gastroenteritis symptoms. On day 11 of the outbreak, the unit was closed to new admissions for 9 days. The outbreak lasted 23 days and declared over after 2 incubation periods of 48 hours since the last identified case. Financial cost was also described. There were no mortalities or escalations of care.
In a review of health care associated gastroenteritis outbreaks in pediatric acute care settings between 1973 to 2024, 293 cases were reported, with a median of 7.5 healthcare-associated cases per outbreak. Rotavirus was the most common cause (14/24) and primarily described before 1990. Norovirus was the second most common cause and predominated after 2000. In available reports, outbreak durations ranged from 8 to 180 days, with a median duration of 29 days and attack rate ranged from 6.6% to 38.7%. Infection prevention (IP) measures described included cohorting of patients and staff to care for infected and noninfected persons, emphasis on hand hygiene, environmental decontamination, visitor or staff exclusion when sick, and unit closure.
Overall, following the licensure of rotavirus vaccines, the incidence of healthcare-associated rotavirus decreased. However, other pathogens, primarily norovirus, may have filled the ecological niche. The advent of more sensitive PCR diagnostics after 2000 also likely helped identify cases in outbreak investigations. IP measures do mitigate spread; however, norovirus can be difficult to control due to multiple modes of transmission, low inoculum needed for infection, and resistance to some disinfectants.
Reference:
L’Etoile N, Zalot MA, Sadaf S, et al. Healthcare-Associated Gastroenteritis: Outbreak Report and Systematic Review of the Literature. J Pediatric Infect Dis Soc. 2025;14(4):piaf019. doi:10.1093/jpids/piaf019 https://academic.oup.com/jpids/article/14/4/piaf019/8042859?login=true