Scientists Discover Hepatitis C Virus Can Remain Infectious Outside of the Body for Up to 6 Weeks
Dr. Ronald Valdiserri
A recent study by researchers from the Yale Schools of Medicine and Public Health revealed that the hepatitis C virus (HCV) can remain infectious for up to 6 weeks on surfaces at room temperature—resulting in a much longer period for potential transmission than was previously appreciated. Prior to this study, scientists believed that HCV could survive for up to four (4) days on surfaces outside of the body. These findings have implications for the safety of patients and workers in healthcare settings as well as for reducing viral hepatitis transmission associated with drug use—both of which are priority areas outlined in the national Action Plan for the Prevention, Care and Treatment of Viral Hepatitis.
“Our findings clearly demonstrate that strict infection control practices and universal precautions are needed in the clinical setting to avoid contact with infectious agents such as HCV that can survive on surfaces,” noted study co-author Professor Robert Heimer of the Yale School of Public Health in a release announcing the study findings. “The implications go beyond the clinic to the risk environment of people who use syringes outside of medical care settings. Unsafe practices, such as sharing of syringes by people who inject drugs or careless handling of human blood during home delivery of intravenous medications, can lead to HCV transmission.”
Implications for Preventing Healthcare-Associated HCV Transmission
The study, funded by the National Institute on Drug Abuse (NIDA), was designed to evaluate the risk of HCV transmission after infectious material dried on environmental surfaces—as might occur in an improperly cleaned blood spill. The investigators found that HCV remained potentially infectious for prolonged periods of time—in some cases as long as six (6) weeks.
This new study supports previous findings indicating that strict adherence to infection control standards and universal precautions are essential to prevent transmission of hepatitis C in healthcare settings. Hepatitis C has been transmitted through improperly used intravenous catheters, blood lancets, and blood glucose monitors. The new Yale study highlights the importance of educating healthcare facility staff, and others who might come in contact with infected blood, on procedures to avoid transmission of HCV and other bloodborne pathogens. The researchers found that commercially available antiseptics (i.e., bleach, CaviCide®, and alcohol) reduce HCV infectiousness on surfaces when used at the recommended concentrations, but not when diluted.
Implications for Preventing HCV Transmission among PWIDs
The Yale study findings of a prolonged period of HCV viability on environmental surfaces also have significant implications for preventing the transmission of HCV among people who inject drugs (PWIDs). Indeed, the study authors conclude that the findings “provide the biological basis for recent observational studies reporting…continued high incidence among people who inject drugs.”
Dr. Jag H. Khalsa
According to Dr. Jag H. Khalsa, Chief of the Medical Consequences of Drug Abuse and Co-occurring Infections Branch at NIDA, “The study has enhanced our understanding of HCV transmission risk, underscoring the resilience and prolonged viability of HCV on a variety of surfaces and objects that can result in infection weeks after contamination. This obviously has serious implications for PWID.” Dr. Khalsa noted that PWID who share any equipment used to prepare or inject drugs (e.g., needles, filtration cottons, “cookers”) are at very high risk for exposure to HCV. The new study findings, Dr. Khalsa explained, suggest that PWIDs could also come into contact with infectious virus on various surfaces or objects weeks after it was left there if the surface or object wasn’t properly disinfected. In addition, people who live in households with PWIDs could also be at risk of exposure to HCV if infected blood is left on environmental surfaces, he noted.
Protecting patients and workers from health care-associated viral hepatitis and preventing viral hepatitis associated with drug use remain two fundamental priorities in our national strategy to combat the “silent epidemic” of viral hepatitis. The Yale study provides important new information that can be used to advance these prevention efforts and educate healthcare workers, patients, persons who inject drugs and their care providers.