I feel entitlement-vibes

> Neither of these things really kick in fast enough to prevent viruses that replicate in the respiratory tract from getting in there, replicating, then going straight back out to infect someone else. That sort of immunity is very hard to attain, which is why no covid vaccine to date prevents transmission, and why the common cold is so incredibly hard to stop.

There is /some/ evidence that nasal spray vaccinations have a degree of better efficacy for preventing covid infection than injected vaccinations. There are many different kinds of T-cells, and 1 variant is specific to the mucosa - a kind of front-line of defence, at the point of entry for respiratory infections. Nasal spray vaccines appear to stimulate immune responses in those mucosal cells a little bit better than muscular injections.

Been a while since I read into this though, and the evidence base was still preliminary and weak/suggestive at that point. I have not followed evidence since, and I do not know if stronger evidence now exists and if so whether it confirms or contradicts the earlier. (I don't think nasal spray covid vaccinations are widely used yet (??), in which case there is unlikely to be any strong evidence yet either).