The objective of the study was to provide immunization policy decision makers with a risk-benefit analysis for pre-adolescents vaccination, for various scenarios regarding the existence and the strength of an association between hepatitis B vaccination and the occurrence of first episode of central demyelinating (FECD) disease. The risks were assessed as the attributable risks of FECD for various time intervals between vaccination and onset of FECD and the benefits as the number of acute fulminant hepatitis B and cirrhosis prevented in a vaccinated annual cohort. Even in the worst-case considered, the number of complications prevented by the vaccination outweighs quantitatively the potential risks. Even if both sides of the balance are of different medical and sociological nature, this result is in favor of reinforcing the pre-adolescent vaccination strategy in France.