Anti vaxer MIL 🙄

So unfortunately my MIL is an anti vaxer. I am very adamant about everyone being vaccinated before they see my baby, especially because I saw the other day that my county is one of the highest in the country to have a likely breakout because there are a lot of anti vaxers here. She wasn’t always so my husband and the older kids are vaccinated but the youngest is 5 so I don’t know if he has any of his vaccinations. I love them all and love her, she just has some weird views on medical stuff. So I don’t want to bar them from seeing my baby, but I’m very worried about the vaccinations and ideally I would like everyone to get the flu shot too since she’s due in Oct. I’m not sure what to do?