Hepatitis B is caused by the hepatitis B virus (HBV), which is spread from person to person through blood, semen, or other body fluids. The virus can be transmitted through various means, including sexual contact, sharing needles or other drug-injection equipment, and from mother to child during childbirth. Additionally, hepatitis B can be spread through needlestick injury, tattooing, piercing, and exposure to infected blood and body fluids, as well as through the reuse of contaminated needles and syringes. The virus can also be transmitted through saliva, vaginal fluids, and semen, and sexual transmission is more prevalent in unvaccinated persons with multiple sexual partners. In highly endemic areas, hepatitis B is most commonly spread from mother to child at birth or through horizontal transmission, especially from an infected child to an uninfected child during the first 5 years of life.
The risk of developing chronic hepatitis B is higher in infants and children, with nearly all newborns who become infected with the virus developing lifelong hepatitis B. Chronic hepatitis B can lead to serious health problems, including liver damage, cirrhosis, liver cancer, and even death. It is important to note that hepatitis B is preventable with a safe and effective vaccine, which is usually given soon after birth with boosters a few weeks later, offering nearly 100% protection against the virus.
