That just seems like a consequence of English having the convention that compound words are written with spaces between them. There is no meaningful difference (apart from the language) between the English "vaccination passport" and the Dutch "vaccinatiepaspoort". For spoken languages, spelling is secondary to speech, so this convention shouldn't matter on whether or not something is a word.

There is surprisingly no all-encompassing definition for "word" in linguistics, but given the fact that you cannot split up "vaccination passport" without either part losing its meaning, it makes sense to award it an entry in a dictionary either way.

You can't split up a sentence without losing its meaning, but it's still comprised of independent words.

Merriam Webster are agents of the elite and these 'COVID terms' have been added to legitimize the tools of our oppressors. Now, they will be with us forever.

This dictionary will show you 'Vaccine Passport', but not 'Nuremberg Code':

https://www.merriam-webster.com/dictionary/nuremberg%20code

https://en.wikipedia.org/wiki/Nuremberg_Code

Vaccine passport is, obviously, a pejorative used for people who hold passports expressly for the purpose of medical tourism.

It would make sense if the word was vaccinepassport. English doesn't lend itself that well to compound words though, like Norwegian or German.