A Yale research team determined that hepatitis C virus can maintain its infectivity for up to 6 weeks on various surfaces, suggesting a potential risk for transmission of the virus in the health care setting.
Elijah Paintsil, MD, of the departments of pediatrics and pharmacology at Yale School of Medicine, and colleagues led by Robert Heimer, PhD, of the School of Public Health, performed a series of experiments to replicate the circumstances in which people may come into contact with HCV dried upon surfaces — such as the preparation of plasma for analysis or the removal of venous lines.
On two separate occasions, the researchers weighed drops of plasma that collected on a foil mat while samples from HIV and HCV-seronegative donors were being prepared for analysis. After weighing 10 accidental drops from each occasion, they calculated the maximum volume of an accidental drop (33 mcL). An equivalent amount of dried plasma spiked with a genetically engineered reporter virus was loaded onto 24-well plates, and samples were either tested immediately after drying or were stored at 4°C, 22°C and 37°C for up to 6 weeks before testing. HCV-negative plasma samples were tested similarly for comparison. The researchers used a microculture assay to determine viral infectivity.
The researchers found that the virus's infectivity was inversely proportional to the temperature at which it was stored. At 4°C and 22°C, HCV from lower titer stocks remained viable for up to 6 weeks, whereas viable HCV was recovered from samples stored at 37°C until day 7 of storage. At lower temperatures, there was a sharp decline in infectivity during the first 2 weeks of storage, followed by "persistent but lower infectivity."
The researchers also investigated the effect of commonly used antiseptics on the viability the virus on contaminated surfaces — including bleach, CaviCide (Metrex) and ethanol — and found that the antiseptics only reduced the virus's infectivity when used at the recommended concentrations, but not when further diluted.
“This study has important implications not only for the safety of laboratory and healthcare personnel, but also for reducing the transmission of HCV within populations of people who inject drugs,” Paintsil told Infectious Disease News. — John Schoen
Elijah Paintsil, MD, can be reached at email@example.com.
Disclosure: The researchers report no relevant financial disclosures.