DALLAS—Neurologists who treat patients with multiple sclerosis (MS) sometimes must consider whether it is safe to administer vaccines to these individuals. The current literature indicates that live and killed vaccines are safe for patients with MS, according to a review presented at the 2014 Cooperative Meeting of CMSC and ACTRIMS.
In addition, current disease-modifying therapies (DMTs) generally do not appear to affect the efficacy of vaccines. Fingolimod is the one DMT that raises concerns, however. Before starting fingolimod in a patient with MS, neurologists routinely assess the patient for an immune response to varicella zoster virus (VZV). If the results are negative, most neurologists will vaccinate the patient before treating him or her with fingolimod, said Patricia K. Coyle, MD, Director of the MS Comprehensive Care Center at Stony Brook Neurosciences Institute in New York.
Patricia K. Coyle, MD
Vaccines, Infections, and Relapses
Several studies suggest an association between benign viral infections and an increased MS relapse rate. One theory is that the infection increases the relapse rate by activating the immune system. As many as one-third of relapses are associated with a prior infection, said Dr. Coyle. “Therefore, vaccines should be beneficial in MS if they prevent infection, so long as they’re relatively safe,” she added. But vaccinations should not be administered during or shortly after relapses.
A 2001 study published in the New England Journal of Medicine followed 643 patients with MS for a four-year period. The patients’ rate of relapses was 2.3% during periods when they received a vaccination, compared with a range of 2.8% to 4% during periods when patients were not being vaccinated. The authors concluded that vaccines are not associated with an increased risk of relapses.
After reviewing studies of vaccines in patients with MS, the MS Council for Clinical Practice Guidelines concluded in 2002 that the evidence supported strategies to minimize infections that can trigger relapses. The panel also concluded that the vaccines for influenza, hepatitis B, varicella, tetanus, and Bacillus Calmette–Guérin were safe for patients with MS. The council endorsed killed vaccines and recommended that neurologists wait for four to six weeks after the onset of a relapse before vaccinating a patient with MS. Physicians should be consulted, however, before administering a live vaccine to a patient receiving an immunosuppressive agent, the panel added.
Specific Vaccines and MS
Researchers also have examined the safety of specific vaccines in patients with MS. The seasonal influenza vaccine may be the best-studied vaccine in this population. The consensus is that the killed virus vaccine is safe, even for patients on a DMT, but that the live vaccine should be avoided.
Three vaccines have raised concerns for patients with MS. Several reports associated the hepatitis B vaccine with demyelinating episodes, but, after reviewing the evidence, the Institute of Medicine concluded that it was safe for patients with MS. Similarly, the literature contains reports of immune-mediated complications of the human papillomavirus (HPV) vaccine in patients with MS, but the vaccine is now accepted as safe in this population.
One case report has discouraged physicians from giving yellow fever vaccine to patients with MS. This vaccine was associated with increased clinical attacks and increased MRI lesion activity, although the report contained a small number of patients. The vaccine is contraindicated in patients who take immunosuppression or immunomodulatory therapies.
A large case–control study presented at the 66th Annual Meeting of the American Academy of Neurology included 780 patients with MS and 3,885 controls. The researchers found no association between an increased risk of demyelinating disease and the hepatitis B vaccine, the HPV vaccine, or any other vaccine. Younger individuals appeared to have an increased risk of CNS expression of disease during the first 30 days after vaccination, but the association was not linked to any specific vaccine. “The ultimate conclusion of this database study was that there was no need to change our current vaccine policy in MS,” said Dr. Coyle.
DMTs and Vaccinations
Researchers also have studied whether DMTs affect a patient’s response to vaccinations. Interferon betas are associated with normal humoral and cellular immune responses to the influenza vaccine. Investigators know of no negative effects of glatiramer acetate that relate to vaccines. Natalizumab is associated with normal humoral responses to the influenza, tetanus, and keyhole limpet hemocyanin vaccines. Researchers found an association between teriflunomide and normal immune responses to the influenza and rabies vaccines. No data about dimethyl fumarate’s effect on vaccine response exist, but the National MS Society does not recommend administering live vaccines to patients with MS who take this drug, said Dr. Coyle.