Hi Karen, that was very kind of you - thanks for getting your vet friend’s input. Im happy to know both yours and hers thoughts on this. I had read a couple articles where they discussed 16 weeks being the sweet spot for lifelong immunity but it sounds like we didn’t get so lucky. I don’t mind boostering him now that I know what his levels are. He’s also a hefty 12.75 pounds and I feel much better about it then I did when he was teeny tiny. Thanks again and god bless.