I have never vaccinated a chicken for anything, and I’ve raised HUNDREDS of them through the years.
I hope they get a handle on this, soon. Eggs are a staple and one of the BEST sources of protein and most of the B vitamins, and also lutein which is good for eyesight.
As always - GROW YOUR OWN when you can. :)
I never vaccinated chickens either and never had a problem with any flock-wide illness, just the occasional bumble foot or egg bound in my older hens.
I quit vaccinating my goats years ago too. I felt the risk of the disease is not worth the risk of the shots. I keep an antitoxin on hand instead (like tetanus)