Hepatitis Transmission Through Saliva
Hepatitis B virus (HBV) can be transmitted through saliva, though the risk is significantly lower than through blood exposure, while hepatitis A and C transmission via saliva is extremely rare.
Hepatitis B Transmission via Saliva
Evidence for Transmission
- HBV has been demonstrated to be present in saliva of infected individuals 1
- Saliva contains lower viral titers compared to blood but can still be infectious 1
- HBV is approximately 100 times more infectious than HIV and 10 times more infectious than HCV 1
- Transmission through saliva has been demonstrated in animal studies where subcutaneous injection of HBV-positive saliva infected gibbons 2
Risk Factors for Transmission
- Presence of blood in saliva significantly increases transmission risk 3
- Human bite with blood involvement can potentially transmit HBV 3
- Transmission through casual contact with saliva (e.g., kissing, sharing food) is extremely rare 1
- No infections have been demonstrated in susceptible persons who had oral mucous membrane exposure to HBsAg-positive saliva in normal circumstances 1
Documented Cases
- Transmission has occurred through human bites in rare circumstances 1
- Only 3 plausible cases of HBV transmission by bites and 1 by spitting have been documented in the literature 3
Hepatitis A and C Transmission via Saliva
Hepatitis A
- Primary transmission route is fecal-oral 1
- Transmission by saliva has not been demonstrated despite detection in saliva during incubation period 1
- No evidence supports saliva as a significant route of transmission 1
Hepatitis C
- HCV RNA can be detected in saliva of infected patients 4, 5
- Only 2 plausible cases of HCV transmission through bites (with blood involvement) have been documented 3
- Epidemiological studies suggest the infective capacity of HCV viral particles in saliva is low 4
- Risk of acquiring HCV through spitting is negligible 3
Prevention of Transmission
Healthcare Settings
- Universal precautions should be followed when handling saliva from potentially infected individuals 1
- Healthcare workers should consider using interpositional airway devices during resuscitation if the patient's saliva is contaminated with blood 1
Household Settings
- Avoid sharing personal items such as toothbrushes or razors with infected individuals 6
- HBV can remain viable on environmental surfaces for at least 7 days 6
- Household contacts of HBV-infected individuals should be vaccinated 6
Clinical Implications
Testing Considerations
- Saliva may be useful for viral detection as part of diagnosis and monitoring of viral hepatitis, though data are inconsistent 7
- Blood testing remains the gold standard for diagnosis of all hepatitis viruses
High-Risk Groups
- Injection drug users, sexual partners of infected individuals, infants born to infected mothers, household contacts of infected persons, and healthcare workers are at higher risk for HBV transmission in general 6
Key Takeaways
- HBV can be transmitted through saliva, but the risk is low without blood contamination
- Hepatitis A and C transmission via saliva is extremely rare
- Prevention strategies include vaccination, avoiding sharing personal items, and following universal precautions in healthcare settings
- The presence of blood in saliva significantly increases transmission risk