Multiple Sclerosis (MS) is a chronic autoimmune condition where the immune system attacks the central nervous system, damaging the protective myelin sheath around nerve fibers. This damage disrupts communication between the brain and the rest of the body, leading to unpredictable symptoms such as fatigue, walking difficulties, and blurred vision. While many individuals with MS wish to donate blood, eligibility rules are complex and prioritize the safety of both the donor and the transfusion recipient. Whether a person with an MS diagnosis can donate depends heavily on their current health status and the specific medications they are using.
General Eligibility and Specific Deferral Criteria
Eligibility varies significantly depending on the country and the specific blood collection organization. In the United States, the diagnosis of MS alone no longer results in an automatic, permanent deferral. This policy change, implemented by the American Red Cross in 2007, followed a scientific review that found no evidence MS is transmissible through blood transfusion. A person with MS in the U.S. can donate if they meet all standard eligibility requirements and are feeling well on the day of donation.
Final eligibility is determined by the screening process, which assesses the stability of the donor’s health. Deferral is typically temporary if a person is experiencing active symptoms, a recent MS flare-up, or is not in a stable phase of the disease. The assessment also considers whether physical limitations, such as mobility issues, might make the donation process difficult or unsafe.
In contrast, many other countries, including the United Kingdom, Canada, and Australia, still permanently defer people with MS. This cautious approach is maintained because the exact underlying cause of MS is not fully understood, and organizations seek to minimize any potential risk to the recipient.
Donor Health and Safety Considerations
Blood collection agencies exercise caution primarily due to the potential risk to the donor’s own well-being during and after the procedure. Blood donation involves the temporary loss of fluid and iron, which can cause a drop in blood pressure and increased fatigue. For a person with MS, who may already experience chronic fatigue or autonomic nervous system issues, these effects can be more pronounced and harder to manage.
The donation process carries a small risk of a vasovagal reaction, a temporary drop in heart rate and blood pressure leading to dizziness or fainting. This physiological stress could potentially exacerbate existing MS symptoms or trigger a relapse in an unstable patient. Therefore, a donor must be in a stable state of health and confident they can tolerate the full process without complications.
Medication Restrictions and Waiting Periods
The use of disease-modifying therapies (DMTs) is a common reason for mandatory deferral, even when the MS condition is stable. These restrictions safeguard the transfusion recipient from the transferred drug, not the donor. Since many DMTs are potent drugs that alter immune function, residual amounts transferred through the blood product could harm an immunocompromised patient.
Blood banks require full disclosure of all medications taken within a specific timeframe, as discontinued drugs can still lead to a waiting period. Certain DMTs, particularly those with a long half-life or a significant impact on cell proliferation, result in substantial deferral periods.
For example, the oral medication teriflunomide (Aubagio) requires a mandatory two-year waiting period after the last dose. This is because the drug persists in the body and is known to cause birth defects, posing a serious risk if the donated blood were given to a pregnant recipient. Other powerful immunosuppressive agents, such as alemtuzumab (Lemtrada) and natalizumab (Tysabri), may also result in long or permanent deferrals due to the risk of transferring an immunosuppressant effect or infection risk to the recipient. The length of the deferral period depends entirely on the specific drug and the potential harm it could cause to a vulnerable patient population.