Think about these numbers: About 90% of infants infected at birth won't show any symptoms but will progress to chronic disease. The risk of hepatitis B infection becoming a chronic disease decreases as the child gets older, becoming about 10% for older children and adults. As you can see, immunizing infants and children for hepatitis B is so important because the risk of developing chronic infection is so much higher for them.
Perhaps you're thinking, "My baby doesn't have hepatitis B now and since she can't possibly be exposed to it for years, she doesn't need another vaccination." This is short-term thinking. Hepatitis B vaccination with a complete series can offer decades of protection. While your baby probably won't be exposed to the virus, she can certainly be exposed as a child, a teenager or an adult. By getting your baby vaccinated now, you'll give her the best chance of protection against hepatitis B.
Source:
Centers for Disease Control and Prevention. July 19, 2008. Viral Hepatitis B.

