"isn't there a vaccine???" unfortunately not, getting a vaccine such as..seeing your friends fish/es, trying to make yourself immune to their look...will only makes things worst LOL.
"also is it true it can be passed down to offspring?" If your offspring/s grow up while you're infected, this is highly possible :P
"nailed it. I have 3 and counting...." you'll keep counting LOL
"I have 2 bettas and the want and potential for a third. " Just wait LOL
I've been trying to stay away whenever I was "cured", and last time I remember when I got infected again, made a promise to myself "5 max, no breeding". But here I am, breaking my own promise again and ended up with..youngsters/adults ( around 40 -50, I don't count, only reminds me of how many times my "promise" multiplied itself ), and now 2 more fries tanks...sigh...