The hepatitis B vaccine is very effective, with over
99 percent of children protected after three doses. There do appear to be some people who do not respond to the vaccine, even after multiple series of vaccines. Some research suggests a genetic basis for this inability to produce hepatitis B antibodies.
The duration of protection from the vaccination is still being studied. In some studies, the protection lasts for over ten years. However, other studies suggest that a significant minority of children, maybe up to 40 percent, have waning immunity as they reach adolescence. Even with the waning immunity, though, it is uncommon to find vaccinated individuals becoming infected with hepatitis B. For that reason, no booster doses have been recommended. The expert thinking is that our measure of immunity is not sensitive enough to evaluate the true protective effect of the vaccine.