Did you get a tetanus shot as a kid? I'm pretty sure I did. Researchers think the shot might lower the risk of MS. Snip:
Dr. Miguel A. Hernan and colleagues from Harvard School of Public Health pooled data from nine studies published between 1966 and 2005 that looked at the association between tetanus vaccination and MS risk. Analyses centered on a total of 963 MS cases and 3126 controls.
They found that a history of having been immunized against tetanus was associated with a 33 percent decrease in risk of MS. The results of the current meta-analysis suggest that tetanus vaccination may prevent or delay the development of MS. The investigators call for further epidemiologic research to assess the role of timing of immunization and the number of doses associated with this protective effect. Link.