Central nervous system demyelinating diseases and recombinant hepatitis B vaccination: a critical systematic review of scientific production.

The etiology of multiple sclerosis has not yet been fully described. A potential link between the recombinant hepatitis B vaccine and an increased risk of onset or exacerbation of multiple sclerosis emerged in the mid-1990s, leading to several spontaneous reports and studies investigating this association. We conducted a critical systematic review aimed at assessing whether hepatitis B vaccination increases the risk of onset or relapse of multiple sclerosis and other central nervous system demyelinating diseases. MEDLINE and EMBASE were used as data sources, and the search covered the period between 1981 and 2011. Twelve references met the inclusion criteria. No significant increased risk of onset or relapse of the diseases considered was associated with hepatitis B vaccination, except in one study. Most studies included in this review displayed methodological limitations and heterogeneity among them, which rendered it impossible to draw robust conclusions about the safety of hepatitis B vaccination in healthy subjects and patients with multiple sclerosis. Therefore, on the basis of current data there is no need to modify the vaccination recommendations; however, there is a need to improve the quality of observational studies with emphasis on certain considerations that are discussed in this review.