FAQ Category: Hepatitis B Causes

Unvaccinated status, multiple partners, unsafe medical practices, living in high-prevalence regions, and weak immunity are the main risk factors.

The main cause is transmission from mother to child during childbirth. Without preventive measures, most infected babies develop chronic hepatitis B.

Chronic hepatitis B develops when the body’s immune system fails to clear the virus. This is common in infants (90%) and less common in adults (5–10%). Genetics, immunity, and co-infections play roles.

Casual kissing does not cause hepatitis B. The virus is not spread through saliva in normal conditions. Only deep kissing with bleeding gums or sores could theoretically pose a minimal risk.

In adults, hepatitis B is most often caused by unprotected sex with an infected partner or sharing contaminated needles. Medical procedures with unsterilized equipment are also important causes in some regions.