Hepatitis B Vaccine Linked to Inflammatory Demyelination
Increased risk seen in children, particularly those with multiple sclerosis, who received Engerix B
THURSDAY, Oct. 9 (HealthDay News) -- Although hepatitis B vaccination usually does not increase the risk of pediatric central nervous system inflammatory demyelination, the Engerix B vaccine may be associated with an increased risk, particularly for confirmed cases of multiple sclerosis, according to a report published online Oct. 8 in Neurology.
Yann Mikaeloff, M.D., Ph.D., of Assistance Publique-Hopitaux de Paris, Service de Neurologie Pediatrique and Centre de Reference National des Maladies Inflammatoires du Cerveau de l'Enfant in Paris, France, and colleagues studied 349 cases with a first episode of acute central nervous system inflammatory demyelination and 2,941 matched controls.
Overall, the researchers found that the hepatitis B vaccination within three years of the index date was not associated with an increased rate of central nervous system inflammatory demyelination (adjusted odds ratio, 0.74). But when they restricted their analysis to vaccination-compliant subjects, they found that vaccination more than three years before index date was associated with an increased trend (odds ratio, 1.50). The trend was especially significant for the Engerix B vaccine (OR, 1.74) and in Engerix B-treated patients with confirmed multiple sclerosis (OR, 2.77).
"Two possible explanations for the differences between brands could be as follows: 1) each vaccine uses a different section of the hepatitis B antigen and some protein fragments produced by yeasts may induce molecular mimicry while others do not; 2) the production process varies by brand and differences in yeast protein content may be crucial if yeast protein may trigger autoimmune reactions: it is stated in the description of Engerix B manufacturing process that the vaccine has no more than 5 percent of yeast proteins, whereas it is no more than 1 percent for GenHevac B," the authors write.