It’s discrimination
Discrimination happens whenever a decision is made that favours one person or group and disfavours another person or group.
For example, as I write the Olympics are drawing to a close. These clearly discriminate against people who are not good at sport.
However, I think you may be confusing “discrimination” with the much narrower class of “unlawful discrimination”. Simply put, discrimination is lawful unless there is a law that says it isn’t.
Unlawful Discrimination
Focussing on Swiss law, Article 8of the Constitution says:
No person may be discriminated against, in particular on grounds of origin, race, gender, age, language, social position, way of life, religious, ideological, or political convictions, or because of a physical, mental or psychological disability.
An argument could be made that a decision not to get vaccinated or tested was a “way of life”, an “ideological conviction” or, from my point of view, a “psychological disability”. As such, a law that discriminated against such people would be unconstitutional.
Except, Article 36 says:
Restrictions on fundamental rights must have a legal basis. Significant restrictions must have their basis in a federal act. The foregoing does not apply in cases of serious and immediate danger where no other course of action is possible.
Restrictions on fundamental rights must be justified in the public interest or for the protection of the fundamental rights of others.
Any restrictions on fundamental rights must be proportionate.
The essence of fundamental rights is sacrosanct.
So, if there is a Federal law mandating vaccine passports and if the government can show that the restriction is “justified” and “proportionate” (which they have a decent shot as) such a law is constitutional.