TETANUS advice plz esp if you are a Vet please

[FairyLights]

I purchased 2 weanling colts in Oct 2010. Had first tetanus vac during first week of my ownership then another a month later. In April 2011 both colts were gelded and the vet gave a tetanus shot and said that neither horses needed a booster "for at least 2 years". Is this correct? I dont want my horses to be unprotected, should they have an annual booster? [If so they are a bit overdue].
Worried Owner

 

[be positive]

Not a vet but they have had their initial protection done correctly, the recommended cover is to then do every other year so not due again until April 2013, you are fine