Actually, a bunch of the doctors that helped create some of these vaccines did deliberately expose themselve to the diseases as proof to the public that it worked. This was back in first part of the 20th century when people couldn't believe that vaccines actually worked as well as claimed. Go read up on how some of them were created. Back then scientists were hardcore and all about proving their stuff was safe and better for the public at large. They felt they had a committment to society to:
1. Make the vaccine.
2. Make the vaccine safe.
3. Make the vaccine effective.
4. Convince the public of #2 and #3, at almost any cost, including their own safety.
Of course, today it would be considered attempted suicide if you deliberately exposed yourself to some of these diseases. But, in a twist of irony it's okay to not vaccinate a child because a parent "is a dumbass".
Some immunologists allegedly died trying to prove that some bogus vaccine worked too!