Available evidence suggests that influenza vaccines do not trigger relapses
of multiple sclerosis (MS), according to an Institute of Medicine (IOM) report.
The report cautioned that current findings are inadequate to determine
whether the vaccines play a causal role in the onset of MS. The committee
said "there is weak evidence for biological mechanisms related to immune-mediated
processes" by which influenza vaccines might act to trigger neurological diseases.
However, committee chair Marie McCormick, of the Harvard School of Public
Health, emphasized that because flu vaccines are so widely administered, the
possible connection between neurological disorders and the vaccines should
be given serious consideration.
Hampton T. No Flu Vaccine–MS Link. JAMA. 2003;290(20):2655. doi:10.1001/jama.290.20.2655-a