A law against spreading infections diseases (HIV, Flu or even covid) exist in many places (my country for example). Hard to prove in court, but the law is there. The principle is, are you ok with having to show a passport for a vaccine to be part of normal society to reduce the risk of catching/spreading a disease.

from CDC:

CDC estimates that the burden of illness during the 2018–2019 season included an estimated 35.5 million people getting sick with influenza, 16.5 million people going to a health care provider for their illness, 490,600 hospitalizations, and 34,200 deaths from influenza (Table 1)

Now, I am not saying that covid is just the flu, but 34k deaths in 2018 from the flu. Does this number also justify having flu shot mandates/passports? Or is it only if it is 340k deaths? 3.4 million deaths? 3k deaths is enough? I heard at a time some people saying 'if it saves only one life, it is worth it' so I wonder how much they will also do for all these other deaths.