Everyone will eventually be exposed to covid (probably repeatedly). It's possible with vaccinations that not everyone will be infected with covid however, as even against omicron it appears 3 doses of vaccine (especially a mix of pfizer and moderna) provide efficacy of 60%+ for at least 15 weeks. Omicron-specific versions of the mRNA vaccines are also already in testing, so I would hope those will be available for future boosters. (Of course there will be future variants as well, but it seems likely those would branch off of Omicron, so an updated vaccine would likely still prove more effective than the current ones would.)
I suppose for some version of "eventually" then everyone would likely expect to get a breakthrough case eventually, but even so the vaccines should drastically reduce the number of times one expects to be infected, so still risk would be reduced, even if it wasn't for breakthrough cases (although it appears that vaccines reduce the risk there as well).
Related to your "exposed to" vs "infected" point, I've been wanting to check my understanding on something, and hopefully someone here can provide a more informed opinion. Immunity can be boosted through exposure, right?
For instance, if someone was vaccinated, but then exposed and was lucky enough not to develop an infection from their exposure, are they immunologically better off as a result of that exposure? I think they probably are, because my understanding is that's how the earliest vaccines worked (exposure on a small enough innoculum to avoid infection) but I'm not an expert, so would love to hear more about this & whether there's a name for such an immune effect when it happens in the wild.
Immunity can be boosted through exposure (indeed, this is one of the reasons why we may be seeing higher rates of shingles in young people, or why we see occasional outbreaks of pertussis in people who were vaccinated awhile back).
But for that, you are, at most, looking for the occasional transient exposure - not the bombardment that one is getting right now.
I saw a blurb about tests of a two part vaccine on mine. First dose an mRNA vaccine injection. Second dose is intranasal naked spike protein. Provided good protection when the mice were challenged. The spike protein isn't infectious. Part of the motivation behind intranasal vaccines is the hope that mucosal immunity provides better protection.
Also read a summary of influenza challenge studies. People exposed to low doses often seroconverted asymptomatically.
I feel it's plausible small exposures after vaccination would build more protection.
It also depends on how many particles it takes to get you sick. Norovirus is only 7, which is insane and also why it spreads so easily. Hard to have just an exposure to that!
China can't stay locked down to the extent they are forever. Hopefully they will have a chance to get their population substantially vaccinated before most there are exposed though.
I suppose for some version of "eventually" then everyone would likely expect to get a breakthrough case eventually, but even so the vaccines should drastically reduce the number of times one expects to be infected, so still risk would be reduced, even if it wasn't for breakthrough cases (although it appears that vaccines reduce the risk there as well).