Hepatitis B is a liver infection caused by the hepatitis B virus. As opposed to hepatitis A, hepatitis B can be a lifelong infection. It is transmitted through contact with infected blood or bodily fluids. Chronic hepatitis B can lead to serious health issues, such as cirrhosis (scarring of the liver) or liver cancer. The CDC reports that there were an estimated 3,050 cases of hepatitis B in the US in 2013. The hepatitis B vaccine is commonly given shortly after a baby is born because babies can contract it via their mothers. Side effects of the vaccine include soreness of the injection site and fever.
