Commentary: A review of risk of hepatitis B and C transmission through biting or spitting

A draft UK Parliamentary Bill sought to criminalize assaults on emergency workers through biting and spitting. This seemed to be based on a fear of bloodborne virus transmission. We undertook a literature search to clarify the risk of hepatitis infection from such exposures. We identified 245 possible papers and then reduced these to those relevant to HBV and HCV transmission through biting or spitting and the scientific plausibility. Nine papers were identified, reporting 16 possible cases of HBV (15 bites, 1 spitting) and 2 of HCV transmission (both bites). Only 3 HBV transmissions by bites and 1 by spitting and both HCV transmissions were felt to be plausible. Although both HBV DNA and HCV RNA can be found in the saliva of infected patients, it seems unlikely that there is enough to transmit infection unless there is blood contamination. In conclusion, the risk of acquiring HCV through spitting is negligible and is very low for HBV. The risk is also low for acquiring HBV and HCV through biting, especially if no blood is apparent in the saliva.