Side effects occurred very rarely during clinical studies or routine use of the vaccine or with individual hepatitis A and hepatitis B vaccines include: • Reduction in blood platelets, which increases risk of bleeding or bruising (thrombocytopenia) • Purple or red brown spots visible through the skin(thrombocytopenic purpura) • Swelling or infection of the brain (encephalitis) • Degenerative disease of the brain (encephalopathy) • Inflammation of nerves (neuritis) • Numbness or weakness of the arms and legs (neuropathy), paralysis