A New Algorithm for Testing Healthcare Workers Exposed to Hepatitis C Virus

The Centers for Disease Control and Prevention (CDC) in an update to its algorithm for testing healthcare workers potentially exposed to hepatitis C virus (HCV) is now recommending an antibodies test 4 to 6 months following exposure. This is based on the agency’s current understanding of early HCV infection viral dynamics. CDC is also calling for preferential HCV RNA tests in source patients to respond to the increasing incidence of acute HCV infection among injectable drug users.

The new report reflects updated guidance from the American Association for the Study of Liver Diseases and the Infectious Diseases Society of America that recommends treatment of acute HCV infection.

Workers treating patients can get exposed through blood, bodily fluids, or sharps injuries. “Although sharps injury prevention measures have led to overall exposure decreases in recent decades, blood and body fluid exposures, including sharps injuries, continue to occur,” wrote the authors of the guidance, who published their recommendations in CDC’s Morbidity and Mortality Weekly Report.

CDC developed this guidance in conjunction with occupational health and viral hepatitis epidemiology experts. 

Guideline authors recommend two pathways for testing source patients: a nucleic acid test or NAT, or an antibody test (anti-HCV), following up with an HCV RNA if positive. NAT is the preferred route, especially when the source patient has engaged in high-risk behaviors such as injecting drugs.

The guideline recommends the following protocol for testing workers:

• Baseline testing for anti-HCV followed by reflex to a NAT for HCV RNA within 48 hours after the exposure. Testing may take place simultaneously with source-patient testing.
• If the source patient’s status calls for follow-up testing (an HCV RNA positive or anti-HCV positive result with unavailable HCV RNA or if the infection status is unknown), workers should receive a NAT for HCV RNA at 3–6 weeks post-exposure.
• If HCV RNA is negative at 3–6 weeks post-exposure, a final test for anti-HCV at 4–6 months post-exposure should take place.
• In the event a worker is exposed to blood or body fluids from a source patient who tests HCV RNA negative but positive for HCV antibody, follow up testing isn’t necessary, except in cases where specimen mishandling compromises test results or if the worker starts showing signs of infection.

Patients or workers with positive HCV RNA results should be referred to further care and evaluation for treatment. Workers who remain anti-HCV negative after 4–6 months don’t require further follow-up, although an additional test for HCV RNA might be considered for individuals with immunocompromised systems or liver disease.

The guideline authors also recommended against HCV post-exposure prophylaxis (PEP) with direct-acting antiviral (DAA) therapy. Their rationale: HCV transmission risk from percutaneous and mucocutaneous exposures is very low. In most cases, it makes no sense to give DAA to exposed healthcare workers due to potential side effects. “Furthermore, efficient duration of PEP has not been established,” the authors added.