Background: The ongoing hepatitis A outbreak in the United States has concerned public health authorities since March 2017. The outbreak has already spread throughout 30 states and includes primarily homeless individuals and persons who use drugs, including persons who inject drugs (PWIDs). Contaminated drug injection paraphernalia and sharing of these items are suspected to be one of multiple causes of hepatitis A virus (HAV) transmission in those populations. Methods: We used a standard plaque assay to investigate HAV infectivity. Liquid suspensions of HAV were tested to examine the effects of time and temperature on viral infectivity. We also examined HAV survival on commonly used drug paraphernalia, such as needles, syringes, cookers, tourniquets, and cotton balls/filters frequently shared among PWIDs. We investigated the effect of low pH on HAV survival using citric acid, which is frequently used by PWIDs during dose preparation. We also compared the plaque assay results with those concurrently obtained by RT-PCR to establish whether viral HAV RNA levels could be used as surrogates for plaque assay results. Results: We found that HAV suspended in PBS at room temperature was able to infect FRhk4 cells for >17 weeks. HAV remained viable in syringes and needles (ie, semidry conditions) for up to 10 weeks depending on the size of the needles and the syringe dead volume. HAV survival in dry conditions on cooker, tourniquet, and cotton balls/filter surfaces did not exceed 4 weeks. HAV retained its infectivity for >10 weeks at pH as low as 2. PCR results suggest that RNA is amplified from both infectious and noninfectious HAV. Conclusions: Our findings show that HAV can survive and remain infective in the PWID setting for 4–10 weeks depending on the type of paraphernalia examined. These findings suggest that sharing drug paraphernalia by the homeless and PWIDs can potentially facilitate the transmission of HAV within these populations. Moreover, our results confirm that the plaque assay is currently the only reliable method to determine the infectivity of HAV in vitro.

Funding: None

Disclosures: None