2011-- FreeOK, I give a talk vaccines, including a bit on herd immunity, and why it is important for everyone, including those of us who are not immunocompromised.
2013-- Started a new job! Had a ton of bloodwork done to get baseline readings, just in case I get exposed to another pathogen.
2014-- Go to Africa, need to make sure my vaccines are all up to date. I have two vaccine cards (a lovely 1970s avocado/lemon/lime green, they should probably be in a museum)--
Physician: "*twists face* This one card says you got one MMR, and this card says you got one too, and I think the dates are different? Its hard to read. Hm. Do you want another MMR?"
Me: "Im pretty darn sure Mom and Dad got me all the shots I was supposed to get, but hey, free MMR! WHOO! Shoot me up!"
2015-- Log into system at work to check other things, realize I can check my baseline readings from 2013:
Me: "Oh neat! *clickyclickyclicky* ... OH GOD I DIDNT HAVE ANTIBODIES TO MUMPS! AHHHH! AHHHHHHHH! I AM THE CARPENTER!!!!"
I *needed* that MMR booster to 'remind' my immune system it knows how to fight mumps! My measles response was fine, my rubella response was fine, it just forgot mumps!
THIS IS WHY EVERYONE NEEDS TO GET VACCINATED.
Shit happens! If everyone gets vaccinated, the few people who are screwed when shit happens, are still protected.
Herd immunity protects EVERYONE.