Here is my story with covid: as far I we know, no infection before jan 2022 when our daughter (12 yo) got cov2 (omicron suspected) with two doses of Pfizer (last one was 2 months earlier). We did not isolate ourselves and neither me or my wife got sick (both pcr tested, no symptoms), we got our third shot 1 months before. Everything went well for a few months, mid may I got covid and passed it to my wife (subvariant unknown, probably too early for BA.5), our daughter was always tested negative. What happens in this case? For sure our daughter was exposed to the virus by both of us and I was convinced she had an additional "natural" booster from us. Apparently it was not the case because last week she came back from a summer school camp with sore throat and was tested positive (this time almost sure it is BA.5). Again, we did not isolate and so far me and my wife are ok (we did not get any test).

Just curious: how does it work in these cases? Can anyone be boosted without being contaminated? I think it was our immunity system that protected us in each case, so I suppose there was somehow a reaction from our bodies.

Bonus question: how would a nasal spray vaccine work differently than exposure to a positive and symptomatic person?