So my vet had us get the puppies vacinations at six weeks old. But now I'm reading on how its not recommaned to get vacinations until 8wks. old due to higher vacination allergies in toy breeds. So now the vet is sending us reminder for their 2nd D2P-PV, is this going to affect them? They JUST got vacinations in march, why a need for another set of the same thing? Does it wear off or something?