“we can agree that this requirement should also apply to immigrants before they are let into our country”
My wife is a family physician who treats a lot of immigrants. She has never had an immigrant family even question a vaccine much less refuse one. Many have received vaccines in their home countries that Americans don’t get such as the tuberculosis vaccine. Only Americans and Israelis seem to be so stupid as to question one of the two greatest public health successes of modern times. (The other is clean water.)