Over the past couple of years there have been a growing number of inquires about the risk of influenza vaccination on MS. The reason for this is two-fold: public health units and employers are now recommending, if not requiring, individuals be vaccinated, and secondly, there is concern that viral illnesses may precede an MS relapse. It is the latter concern that led to studies demonstrating no increased risk of relapse or neurological deterioration after influenza vaccination. In addition, our experience in the clinic would support these results. There is no contraindication for patients on immunomodulating therapies (i.e. interferon or glatiramer acetate) to be vaccinated, however, patients on treatment should have pre-assessment of leukocyte counts and approval by their family doctor.
MS flares can be triggered by a bout of influenza. About one-third of patients worsen following the flu. The risk is much less following vaccination (1/20). The risk to benefit ratio favours vaccination.