Blood-borne viruses and their survival in the environment: is public concern about community needlestick exposures justified?

BACKGROUND: More than 30 million needle syringes are distributed per year in Australia as a component of harm-reduction strategies for injecting drug users (IDU). Discarded needle syringes create considerable anxiety within the community, but the extent of needlestick injuries and level of blood-borne virus transmission risk is unclear. We have undertaken a review of studies of blood-borne virus survival as the basis for advice and management of community needlestick injuries.
METHODS: A Medline review of published articles on blood-borne virus survival and outcome from community injuries.
RESULTS: Hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) can all survive outside the human body for several weeks, with virus survival influenced by virus titer, volume of blood, ambient temperature, exposure to sunlight and humidity. HBV has the highest virus titers in untreated individuals and is viable for the most prolonged periods in needle syringes stored at room temperature. However, prevalence of HBV and HIV are only 1-2% within the Australian IDU population. In contrast, prevalence of HCV is 50-60% among Australian IDUs and virus survival in needle syringes has been documented for prolonged periods. There have been no published cases of blood-borne virus transmission following community needlestick injury in Australia.
CONCLUSION: The risk of blood-borne virus transmission from syringes discarded in community settings appears to be very low. Despite this, procedures to systematically follow up individuals following significant needlestick exposures sustained in the community setting should be developed.