Dealing with in-laws kissing my newborn

When my little lady was 8 days old we had our first set of visitors from hubby’s side of the family. There was 4 of them that came for a 3hr visit, 2 of them had just returned from a holiday in Thailand and had a stomach bug whilst there. They no longer had any symptoms so I was ok with them holding our daughter but we both said no kissing please, 2 of them blatantly ignored our request and said they’d been kissing babies all their life with no harm after giving her a kiss on her hands and head 2 seconds after we told them not to 😤🤯...

At 5 weeks old she is full of cold and they come to visit. Two of them kiss her on the head and the other two remember me stating not to last time so they asked if they could. I said not in the first 3 months before her vaccinations and she’s not well at the moment, so doesn’t need to be catching anything else. They ignored me AGAIN anyway and kissed her.

On both occasions I looked at hubby in horror and washed her hands and head after they left. I’m still upset that they went against our request... hubby has just put it down to typical old people. I’m STILL so annoyed! I feel even more protective over our lady now and don’t want them to visit again... worse still I’m worried about future things like this happening and then going against my expressed wishes. My MIL has requested to stay for a whole week through my husband too and I’m worried about what our differences in opinions on general things will do... shall I grin and bare a visit? How do I put my foot down in future without causing rifts?!