HBV is spread by direct contact with blood or body fluids of an infected person, such as:
- Unprotected sexual contact
- Blood transfusion
- Sharing of contaminated needles and syringes
- Vertical transmission from mother to child during childbirth
Contact via the lips could also cause the spread of the virus, especially if the infected person has a cut on their lip. However, the virus is not shed in the saliva.