Are live vaccines a no-no for people with MS? #ClinicSpeak #MSBlog #MSResearch
“Most people diagnosed with MS analyse their lives and look for ‘potential causes’ for their MS. It is not surprising that vaccinations get fingered as being the trigger, or cause, of MS in many people. The evidence suggests the contrary (see review below). MS is relatively common and vaccinations are even more common, therefore by chance MS is going to present in some people shortly after they have had a vaccination. Therefore we have to rely on large population studies to see if there is any temporal (timing) relationship between vaccinations and MS. To the best of my knowledge the answer is no; we have no evidence that MS is caused by, or related, to any vaccine.”
“With regard to relapses the evidence is less certain, simply because not all vaccines have been systematically studied. In relation to inactivated component vaccines, for example influenza and hepatitis B, there is no convincing evidence that would indicate that these vaccines trigger relapses. In relation to live vaccines I don’t know. I say I don’t know is that we know that infections are a well-defined, and studied, trigger of relapses. Approximately a third of relapses occur in the at-risk period (last 4-6 weeks) in relation to a recent infection. Live vaccines work because they are an infection, albeit an attenuated infection, with a virus or bacteria that is derived from a known human pathogen. This is why I always warn my patients with MS about live vaccines; live vaccines have the potential to trigger relapses. As always the decision to have a live vaccine is an individual one; a personalised risk:benefit decision about whether or not to have a vaccine to protect you against a potential infection and the undefined risk the vaccine may trigger an MS attack. For those of you on immunosuppressive DMTs live vaccines are generally a no-no, so the decision has already been made for you.”
“What this post tells me is that there is a lot we still don’t know about MS and how it relates to general immune function. May be when we know the cause of MS we will be able answer the questions about the safety of vaccines in people with MS based on evidence and not opinion.”
Nguyen et al. Vaccine-associated inflammatory diseases of the central nervous system: from signals to causation. Curr Opin Neurol. 2016 Mar 26.
PURPOSE OF REVIEW: As the most cost-effective intervention in preventive medicine and as a crucial element of any public health program, vaccination is used extensively with over 90% coverage in many countries. As approximately 5-8% of the population in developed countries suffer from an autoimmune disorder, people with an autoimmune disease are most likely to be exposed to some vaccines before or after the disease onset. In fact, a number of inflammatory disorders of the central nervous system have been associated with the administration of various vaccines. These adverse events, be they spurious associations or genuine reactions to the vaccine, may lead to difficulties in obtaining public trust in mass vaccination programs. There is, thus, an urgent need to understand whether vaccination triggers or enhances autoimmune responses.
RECENT FINDINGS: By reviewing vaccine-associated inflammatory diseases of the central nervous system, this study describes the current knowledge on whether the safety signal was coincidental, as in the case of multiple sclerosis with several vaccines, or truly reflected a causal link, as in narcolepsy with cataplexy following pandemic H1N1 influenza virus vaccination.
SUMMARY: The lessons learnt emphasize a central role of thorough, ideally prospective, epidemiological studies followed, if the signal is deemed plausible or real, by immunological investigations.