An outbreak of hepatitis C virus attributed to the use of multi-dose vials at a colonoscopy clinic, Waterloo Region, Ontario

BACKGROUND: Hepatitis C virus (HCV) transmission has been epidemiologically linked to healthcare settings, particularly out-of-hospital settings such as endoscopy clinics and hemodialysis clinics. These have been largely attributed to lapses in infection prevention and control practices (IPAC). OBJECTIVE: To describe the public health response to an outbreak of HCV that was detected among patients of a colonoscopy clinic in Ontario, and to highlight the risks of using multi-dose vials and the need for improved IPAC practices in out-of-hospital settings. METHODS: Screening for HCV was conducted on patients and staff who attended or worked at the clinic within the same timeframe as the index case's procedure. Blood samples from positive cases underwent viral sequencing. Inspections of the clinic assessed IPAC practices, and a chart review was done to identify plausible mechanisms for transmission. OUTCOME: A total of 38% of patients who underwent procedures at the clinic on the same day as the index case tested positive for HCV. Genetic sequencing showed a high degree of similarity in the HCV genetic sequence among the samples positive for HCV. Chart review and clinic inspection identified use of multi-dose vials of anesthesia medication across multiple patients as the plausible mechanism for transmission. CONCLUSION: Healthcare workers, especially those in out-of-hospital procedural/surgical premises, should be vigilant in following IPAC best practices, including those related to the use of multi-dose vials, to prevent the transmission of bloodborne infections in healthcare settings.