Hello, Twinrix is a vaccine that is used to prevent hepatitis A and hepatitis B infections. It is a combination vaccine that contains inactivated hepatitis A virus and recombinant hepatitis B surface antigen. There have been some concerns about whether the Twinrix vaccine could be linked to an increased risk of multiple sclerosis (MS), a chronic autoimmune disease that affects the central nervous system. However, studies have not found any evidence to suggest that Twinrix or any other vaccine increases the risk of developing MS. In fact, the available evidence suggests that vaccines, including Twinrix, do not increase the risk of MS or exacerbate existing MS symptoms. The National Multiple Sclerosis Society and the Centers for Disease Control and Prevention (CDC) recommend that people with MS get vaccinated according to the same schedules as people without MS, unless otherwise directed by their healthcare provider. As with all vaccines, Twinrix may cause some side effects, such as soreness or redness at the injection site, headache, fatigue, or mild fever. These side effects would generally be mild and will go away on their own within a few days. If you have concerns about the Twinrix vaccine or any other vaccine, you should discuss them with your healthcare provider. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Shah Hussain, General & Family Physician