Background: Since 1994, the hypothesis of a potential causal relationship between vaccination against hepatitis B and multiple sclerosis (and other demyelinating diseases) was brought to the attention of the French health authority, and to public debate. In Italy, since 1991, vaccination against hepatitis B has been mandatory for newborns and 12-year-old children, and also recommended for high-risk groups.
Aim: To re-evaluate the risk/benefit profile of the Italian strategy of hepatitis B vaccination.
Subjects: The study population is a hypothetical cohort of 100,000 newborns.
Methods: We present a simulation of the hepatitis B cases that could be prevented with the vaccination and of the potential excess of multiple sclerosis cases which would occur, assuming different odds ratios of multiple sclerosis among vaccinees, and by effecting the vaccination at different ages.
Results: In the cohort, we would expect 1,099 hepatitis B cases, that would be prevented with vaccination. Assuming that the highest odds ratio of 1.7 reported is true, the excess of "life-time" multiple sclerosis incidence would be 0.3% for 12-year-old subjects, and 2.9% for adults.
Conclusions: On the basis of these data, our opinion is that the hepatitis B vaccination strategy presently adopted in Italy for newborns, teen-agers and high risk groups should not be modified.