Mother in law is anti-vax

My mother in law has recently decided she does not believe in vaccines (meaning she vaccinated my husband and his sibling as children) and is refusing to get a TDAP vaccine (or flu shot or anything for that matter). The plan was for her to watch our baby for a few hours a week when I go back to work after 6 weeks to allow my husband, who works a night shift, to get a few hours of sleep. I no longer feel comfortable with this plan and she told my husband if we feel the need to limit her time around the baby that is our choice.

My question is: how much would you stick to limiting her time around the baby? Am I being bitchy for being upset and worried?

Please no comments if you do not believe in vaccines, I'm curious for those who do believe in the science to give their point of view.