Here is an article about vaccinating laying hens.I did not know about salmonella vaccination protocols in Europe. I live in Italy and no one I know refrigerates eggs ever. If I have an egg that requires washing, I might cook it immediately after washing and feed it to the chickens. Or I might refrigerate it.
It's a good one.
https://www.nytimes.com/2010/08/25/business/25vaccine.html