Control of a Norovirus Outbreak in a Five-Facility Medical Campus

Background: Norovirus healthcare-associated outbreaks are difficult to control because of efficient person-to-person transmission and the virus’ stability in fomites and its resistance to common cleaning agents.
Objective: To assess the impact of early identification and of early implementation of strategies on a norovirus outbreak in a 5-healthcare facility campus.  Methods: Infection Prevention was notified of a cluster of an acute gastrointestinal illness in 6 patients in the Rehabilitation Unit (RU).  Expanded surveillance detected illness in 6 physicians and 2 administrators occurring on the same day.  A case was defined as a healthcare provider (HCP) or patient who acutely develops nausea, vomiting, or diarrhea with fever and prostration with resolution within 72-96 hours.

Infection Prevention organized a meeting on the 2^nd day of the outbreak when an additional 6 RU patients became ill.  The group consisted of HCPs from RU, administration, Employee and Occupational Health (EOHD), environmental and food services to discuss control strategies.  Because of the acuteness of symptom onset and the rapid spread of the infection, a norovirus infection was suspected.  The RU was closed to new admissions, contact precautions implemented for ill patients, visitation was restricted, therapy in the gymnasium was suspended, and targeted disinfection of the patient care areas with bleach solution was initiated.  Hand hygiene was stressed and HCPs were instructed to observe that all patients clean their hands with alcohol impregnated disposable towelettes before eating.  Selected stool samples were submitted for studies including norovirus detection by polymerase chain reaction.

When it became apparent that there were cases outside of the RU and that HCP were involved, Infection Prevention intensified its surveillance and implemented strategies throughout the 5 healthcare facilities.  Ill HCPs were instructed not to return to work until 48 hours after resolution of symptoms.  Early on, the kitchen was not identified as a potential source of the outbreak.  EOHD received daily logs of HCP absenteeism.  Daily meetings were held until there was control of the outbreak.

Results: The number of patients identified as meeting the case definition was 45; 15 were laboratory confirmed as having norovirus. 122 HCPs meet the case definition.  It is likely that the actual number of HCPs that met the case definition was much higher due to reporting bias.  The outbreak would eventually terminate approximately three weeks after the initial index cases were identified.

Conclusions: The outbreak was terminated with prompt identification of the virus and after implementation and documentation of adherence to multiple infection prevention strategies: hand hygiene, observed use of alcohol impregnated towelettes by patients before meals, targeted environmental cleaning with bleach, unit closures, and consistent communication to staff regarding the status of the outbreak.