Last edited 06/2018 and last reviewed 03/2022

HBV is present in high concentration in the blood and bodily fluids of many hepatitis B virus carriers.

Transmission predominantly occurs through percutaneous or mucosal exposure to infected blood and various body fluids, including saliva, menstrual, vaginal, and seminal fluids

  • sexual transmission
    •  particularly in unvaccinated men who have sex with men and heterosexual persons with multiple sex partners or contact with sex workers.
  • accidental inoculation of minute amounts of blood or fluid
    • during medical, surgical and dental procedures
      • there is a 30-40% chance of transmitting the infection to a susceptible contact via a needlestick injury
    • intravenous and percutaneous drug abuse
      • account for over 20% of identified UK acute cases
    • from razors and similar objects contaminated with infected blood
    • use of inadequately sterilized syringes and needles
    • tattooing; body piercing; and acupuncture
  • perinatal transmission
    • is a major route of HBV transmission in many parts of the world
    • infection may transmit at the time of, or shortly after birth
      • transmission in utero appears to be uncommon and is generally associated with antepartum haemorrhage and placental tears
    • risk of perinatal infection is also increased if the mother has acute hepatitis B in the second or third trimester of pregnancy or within two months of delivery
    • risk of developing chronic infection is 90% following perinatal infection (up to 6 months of age) but decreases to 20–60% between the ages of 6 months and 5 years (1)