Personal and population-level benefits
“There is no evidence that vaccination increases the risk of MS exacerbation, although the literature is sparse,” the authors said. “In addition to conferring personal benefits, vaccination of the MS patient population contributes to the well-established phenomenon of herd immunity for the communities in which patients with MS live,” the authors wrote.
Because influenza infection has known risks of exacerbation and morbidity, whereas influenza vaccine has no identified risks of exacerbation, “benefits of influenza vaccination outweigh the risks in most scenarios, although patients with MS receiving some [immunosuppressive or immunomodulating] treatments (fingolimod [Gilenya], glatiramer acetate [Copaxone], and mitoxantrone) may have a reduced response to influenza vaccination,” the authors said. Studies in patients with diseases other than MS suggest that rituximab (Rituxan) also may be associated with reduced influenza vaccine responsiveness.
Immunosuppressive or immunomodulatory medications including alemtuzumab (Lemtrada), dimethyl fumarate (Tecfidera), fingolimod, mitoxantrone, natalizumab (Tysabri), ocrelizumab (Ocrevus), rituximab, and teriflunomide (Aubagio) have been associated with severe occurrences or recurrences of vaccine-preventable infections, and many package inserts approved by the Food and Drug Administration provide guidance regarding immunization with live vaccines and treatment.
Prescribing information for alemtuzumab, fingolimod, ocrelizumab, and teriflunomide recommends against the use of live vaccines during and immediately preceding treatment. Furthermore, the prescribing information recommends waiting 2-6 months after treatment to immunize with live vaccines, depending on the half-life of the specific therapy.
“The guideline panel identified no evidence that vaccines increase the risk of relapse or worsen relapse severity, but studies are limited,” Dr. Farez and colleagues wrote. “Experts remain concerned that vaccines may worsen relapse severity if given to patients who are actively experiencing an MS relapse.” In addition, use of glucocorticoids may raise concerns about the safety of live-virus vaccines. “Immunization is not typically an urgent need and, in most cases, can be temporarily delayed without a marked increase in infection risk,” the guideline says.
Few high-quality studies
Data were lacking or insufficient to assess whether most vaccine-preventable diseases increase the risk of MS exacerbations. “It is probable that individuals with active MS exacerbations have higher odds of varicella zoster virus viral DNA present in peripheral blood mononuclear cells than individuals with MS in remission,” the guideline says.
Human papillomavirus, pertussis, and tetanus toxoid vaccinations probably are associated with a lower likelihood of a subsequent MS diagnosis, and smallpox vaccination is possibly associated with a lower likelihood of a subsequent MS diagnosis, the review found.
Studies included in the systematic review did not address whether live-attenuated vaccines are as effective in patients with MS as they are in the general population. With regard to the effectiveness of inactivated vaccines, patients with MS possibly are less likely to have a sufficient response to influenza vaccination, compared with controls.
The systematic review “found few high-quality studies to inform recommendations,” the authors said. “As more [immunosuppressive or immunomodulating] agents are developed to manage chronic diseases such as MS, long-term prospective cohort studies are required to evaluate both the safety and effectiveness of immunizations in MS.”
Dr. Farez has received funding for travel from Teva Argentina, Novartis Argentina, and Merck Serono Argentina and has received research support from Biogen. Coauthors’ disclosures included financial ties to pharmaceutical companies.
SOURCE: Farez M et al. Neurology. 2019 Aug 28. .