As some medications for MS have a considerable effect on the function of the immune system, there have been concerns that people using these medications may not gain protection from vaccinations against infectious disease.
However, new research, published in the prestigious journal Neurology, has shown that seasonal vaccines such as the influenza vaccine, and standard booster vaccines such as tetanus, may still be effective in many people with MS being treated with disease-modifying medications such as fingolimod.
This study was conducted across multiple sites by an international team of researchers, led by Dr Ludwig Kappos from the University of Basel, Switzerland, in collaboration with researchers from Spain, Poland, USA and India.
The researchers studied 136 people with relapsing remitting MS, who were randomly allocated to receive either fingolimod or placebo for 12 weeks. After 6 weeks of treatment, all participants received both a seasonal influenza vaccine and a tetanus toxin booster vaccine.
Vaccines activate the body’s natural defences against infection, by stimulating the B cells of the immune system to produce antibodies against a virus or bacterium, without actually producing the symptoms of infection. These antibodies help to sensitise the immune system against the target infection (e.g. tetanus or influenza), so that if the body is later exposed to the same infection the antibodies can respond much faster and more strongly, and stop the infection taking hold.
This study is very important because disease-modifying treatments such as fingolimod substantially modify the function of the immune system, including B cells, and could result in reduced vaccine effectiveness.
Following vaccination, the researchers measured the levels of antibodies to the influenza virus and the tetanus bacteria and compared these levels between the fingolimod and placebo groups, to determine whether the vaccines were effective in stimulating an immune response.
Six weeks after the vaccination, the results showed that almost half (43%) of the people treated with fingolimod were adequately protected by the vaccine against influenza, and 38% were protected against tetanus. However, this number was higher in the placebo group (75% for influenza and 49% for tetanus), suggesting that fingolimod did reduce the rate of people receiving adequate vaccine protection. Importantly, the rates of adverse events were not substantially different between the two groups.
The authors conclude that fingolimod did not completely inhibit the effectiveness of the influenza or tetanus toxin vaccines, and the vaccines still met regulatory criteria for immune protection in this group of people. They advise that clinicians should take into account that vaccine effectiveness may be slightly reduced for people receiving disease-modifying MS medications compared to the general population.
This is important evidence to suggest that people with MS being treated with fingolimod should speak with their neurologist or regular clinician to determine if these vaccinations are suitable or necessary for their individual circumstances, and to ensure that they gain adequate protection against infectious disease where possible.