Interesting?

I was very happy (no actually I was beside myself) to have my horse (in a purple zone) receive his 1st vaccination today. When I enquired about the 2 week booster shot I was told, by the vet, that they (I assume the DPI) have now learned that a horse has more immunity if the booster is given 1 month after the 1st injection and then they don't require the 6 month injection. Does anyone else smell a rat.

Judy