For individuals affected by multiple sclerosis (MS), vaccination brings questions and concerns. The relationship between the immune system and MS makes any discussion about vaccines feel weighty. Navigating immunizations while managing a chronic illness can seem complex, but understanding the scientific evidence is the first step. This article provides information to help patients make informed choices with their healthcare providers.
The Disproven Link Between Vaccines and MS Onset
A common concern is whether a vaccine can cause a person to develop MS. This fear originated from discussions in the 1990s surrounding the hepatitis B vaccine. It was hypothesized that the vaccine could trigger the autoimmune response that leads to MS in some susceptible individuals.
Over the past few decades, numerous large-scale studies have addressed this question. These investigations have consistently found no evidence of a causal relationship between any vaccine and the onset of MS. Reviews have confirmed no association for vaccines against hepatitis B, HPV, influenza, and measles, mumps, and rubella (MMR).
The global scientific and medical consensus is that vaccines do not cause MS. While some reports note a temporal association—meaning MS symptoms appeared after a vaccination—these are considered coincidental rather than causal. The mechanisms of MS are complex, but extensive research has ruled out immunization as a trigger for the disease.
Vaccination’s Role in MS Relapses
For those already diagnosed with MS, a related question is whether a vaccine can trigger a relapse. Since vaccines work by activating the immune system to build protection, it is a logical concern. Any stimulation of the immune system carries a theoretical possibility of increasing disease activity in an autoimmune condition like MS.
Major studies have shown that vaccination does not increase the overall risk of a relapse. A large study found no significant association between recent vaccination and hospitalization for a relapse. Similarly, reviews of vaccines for influenza, tetanus, and hepatitis B found they did not increase the short-term risk of relapse. Some people may experience temporary “pseudo-relapse” symptoms like fatigue due to a fever after a shot, but these are not true relapses.
It is important to contrast the low, theoretical risk from vaccination with the proven risk of relapse from infections. Contracting influenza, COVID-19, or other vaccine-preventable diseases is documented to increase the likelihood of an MS flare-up. The protection afforded by vaccines is a strategy for preventing illnesses that can destabilize the disease. The consensus is that the benefits of preventing infection far outweigh the risk from the vaccine.
General Vaccine Guidelines for Individuals with MS
Navigating vaccine recommendations involves understanding the two main categories: inactivated and live-attenuated. The distinction is central to vaccination guidelines for people with MS. Inactivated, or “killed,” vaccines use a non-infectious version of a virus or bacteria and are considered safe. Examples include most injectable flu shots, tetanus shots, and the inactivated polio vaccine.
In contrast, live-attenuated vaccines contain a weakened but active virus, such as in the measles, mumps, and rubella (MMR) and chickenpox vaccines. These are generally not recommended for people with MS, particularly those on immune-suppressing medications. The concern is that a modified immune system may not control the weakened virus, leading to a potential infection.
The American Academy of Neurology advises that people with MS follow standard vaccination schedules but avoid live-attenuated vaccines. An exception might be considered for a patient not on immune-suppressing therapy who needs protection against a specific disease. This requires a careful discussion of risks and benefits with a neurologist.
Coordinating Vaccines with MS Medications
The interaction between vaccines and disease-modifying therapies (DMTs) is a main consideration in developing a vaccination plan. Many DMTs for MS work by suppressing the immune system to reduce disease activity. This can reduce a vaccine’s effectiveness and increase the risks associated with live vaccines.
Certain DMTs, such as B-cell depleting therapies like ocrelizumab (Ocrevus), can blunt the body’s ability to produce antibodies in response to a vaccine. This means the patient may not develop a robust immune memory. To maximize effectiveness, timing is an important factor. For infusion therapies, it is recommended to administer vaccines a set period after the last DMT dose and before the next, such as 12 weeks after the last infusion and at least four weeks before the next.
For other medications, such as alemtuzumab (Lemtrada), there are specific windows to wait after treatment before vaccination is considered safe. Creating a safe and effective vaccination schedule requires a personalized plan. Patients must consult their neurologist before receiving any vaccine to coordinate it with their specific DMT regimen.