Notes From the Field

Investigation of Hepatitis C Virus Transmission Associated With Injection Therapy for Chronic Pain — California, 2015

Monique A. Foster, MD; Cheri Grigg, DVM; Jaclyn Hagon, MSN; Paige A. Batson, MA, Janice Kim, MD; Mary Choi, MD; Anne Moorman, MPH; Charity Dean, MD


Morbidity and Mortality Weekly Report. 2016;65(21):547-549. 


On November 26, 2014, the California Department of Public Health (CDPH) contacted CDC concerning a report from the Santa Barbara County Public Health Department (SBPHD) regarding acute hepatitis C virus (HCV) infection in a repeat blood donor. The patient, who was asymptomatic, was first alerted of the infection by the blood bank and had no traditional risk factors for HCV infection. The donor had a negative HCV nucleic acid test (NAT) 56 days before the first positive NAT test, and an investigation into the donor's health care exposures and other potential risk factors, including injection drug use, incarceration, and long-term hemodialysis within this narrow exposure window, was conducted by SBPHD.

One such exposure occurred at a doctor's office (clinic A) where the blood donor received an injection procedure as part of prolotherapy. Prolotherapy, also known as regenerative injection therapy, is an increasingly popular, injection-based complementary and alternative medical therapy used to treat chronic musculoskeletal pain.[1] Common substances injected include hypertonic dextrose, phenol-glycerine-glucose, and morrhuate sodium, a mixture of saturated and unsaturated fatty acids from cod liver oil.[1] In addition, some patients also received platelet rich plasma therapy, a method of prolotherapy that involves injection of autologous blood with a high platelet-to-plasma ratio.[2] No formal practice guidelines have been established for prolotherapy treatment, and no formal training is required to deliver this service. The initial investigation into clinic A revealed infection control breaches that included reentering multidose medication vials with a used syringe, use of single-dose medication vials for multiple patients, poor hand hygiene and inconsistent glove use, and lack of aseptic technique when handling injection equipment and medication. Clinic A was advised to stop these practices, and staff members were educated on bloodborne pathogen transmission. A subsequent visit to clinic A revealed ongoing poor infection control practices by staff members. After this visit, the county health officer issued an order to close clinic A immediately. A joint investigation into clinic A by SBPHD, CDPH, and CDC was initiated to identify additional cases and determine the source of transmission.

Patients who visited clinic A during the preceding 10 months (n = 400) were notified through mailed letters about their potential exposure to HCV, hepatitis B virus (HBV), and human immunodeficiency virus (HIV). SBPHD coordinated free testing through a local laboratory. Case-finding activities included review of medical records for patients who visited clinic A, review of state hepatitis surveillance records and crossmatching with clinic A records, and serologic HCV and HBV testing of staff members. Patients subsequently identified as having HCV infection were interviewed, and a blood specimen was sent to CDC for HCV genotype and phylogenetic testing.

In addition to the index patient, six other patients who received injections at clinic A were determined to have HCV infection by serologic testing. Among these six patients, five were unaware of their HCV infection status. Four of the patients without a prior HCV diagnosis or risk factors for HCV had injection procedures performed in clinic A on the same day as the index patient. A common injected substance used in all the infected patients was not identified through medical chart review, although documentation of injected local anesthesia was inconsistent. No new HBV or HIV infections were found.

Identification of a case of acute HCV infection in a frequent blood donor without other risk factors should be considered a sentinel event and should prompt public health investigation, because this could indicate a possible health care–associated infection.[3] HCV transmission from health care exposures has been documented previously ( Table ).[4,5] Many of these outbreaks are attributable to the same unsafe injection practices observed in clinic A, namely reuse of syringes to access medications used for multiple patients.[5] Although hospitals have established infection control education, resources, and oversight, health care settings where complementary and alternative medical therapies are administered, especially those that involve injections, might benefit from infection control training and inclusion in health care–associated infection surveillance networks, such as CDC's National Healthcare Safety Network.[6] All health care settings, including complementary medical settings where injections occur, should follow guidelines for safe injection practices.[7]