Hepatitis C Virus Remains Infective for 6 Weeks on Fomites

Lara C. Pullen, PhD

December 09, 2013

Drops of hepatitis C virus (HCV) dry and remain infective for 6 weeks at room temperature, according to a new study. Therefore, fomites may be a source of nosocomial HCV infections. The persistence of the virus on fomites may also underlie the continued high incidence of HCV infection among people who inject drugs.

Elijah Painstil, MD, from the Department of Pediatrics the Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut, and colleagues published their microculture assay results online November 23 in the Journal of Infectious Diseases. They designed their study to mimic the natural events that might lead to the transmission of HCV, using a genetically modified HCV laboratory clone that was derived from a genotype 2a virus.

Drops of plasma spiked with the 2a HCV reporter virus were placed into a 24-well plate and stored uncovered for up to 6 weeks. The drops ranged from 20 to 33 μL (mean volume, 29 μL). The investigators performed the experiment 3 times.

"In our simulation of real world risks of HCV transmission in settings conducive to exposure to HCV-contaminated fomites, we observed that [cell culture derived HCV (HCVcc)] could maintain infectivity for up to 6 weeks at 4° and 22°C. This finding supports our hypothesis that the increasing incidence of nosocomial HCV infections may be due to accidental contact with HCV-contaminated fomites and other hospital equipment even after prolonged periods after their deposition. Moreover, we found that HCVcc infectivity was influenced by HCVcc viral titer and the temperature and humidity of the storage environment," the authors write.

They add that all of the HCVcc-contaminated drops dried within 4 hours at room temperature and became easy to overlook. Dried drops are thus a challenge for infection control and are possibly a source of accidental exposure to HCV. "[G]iven the infection control implications of our findings, we decided to investigate if commonly used antiseptics are effective against HCV. We demonstrated that bleach, cavicide, and ethanol are effective at their recommended concentrations," the authors elaborate.

Commercial antiseptics did vary in their anti-HCV activity. Bleach (diluted 1:10) was more effective than cavicide (diluted 1:10), which was more effective than ethanol (70%).

This study was made possible by grant from National Institutes of Health/National Institute on Drug Abuse. The authors have disclosed no relevant financial relationships.

J Infect Dis. Published online November 23, 2013. Full text


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