Hepatitis C Virus Cluster at a Pain Clinic — Los Angeles, 2022

Background: During October 2022, the Los Angeles County Department of Public Health (LACDPH) was noti-fied of a patient with acute hepatitis C virus (HCV) infection with no known risk factors, that had been treated previously at a local pain clinic.We investigated to determine a source and prevent further infections.Population and methods: We reviewed medical records to confirm the patient's illness met the Council of State and Territorial Epidemiologists' case definition for acute HCV infection.We interviewed the patient regarding HCV risk factors during 6 months before symptom onset and conducted an assessment of the pain clinic.We matched names of patients who received procedures at the pain clinic ≤28 days before the index patient to the LACDPH HCV registry.We reviewed medical records for patients with HCV who had procedures the same day as the index patient, and collected blood for whole-genome sequencing.Results: Of 127 pain clinic patients, 1 with chronic and 1 with acute HCV infection matched with the HCV registry.All 3 patients had HCV genotype 1b infections and had procedures requiring anesthesia performed on the same day.Propofol and lidocaine were used for anesthesia; only lidocaine was in a multidose vial and was found inside the procedure room.The chronic HCV patient had the first procedure of the day, followed by the 2 acute HCV patients.Conclusions: Identification of an uncommon HCV genotype (1b) and the temporal association of 2 acute cases in patients with similar procedures performed immediately after a patient with chronic HCV infection provided substantial evidence for HCV transmission from the medical procedures.A multidose vial used in the procedure room might have been inadvertently contaminated.Our investigation reinforces the importance of keeping multidose vials in the central medication area and taking only the needed dose to the procedure room.