In terms of our symptoms/timeline: My wife had symptoms (primarily feeling lightheaded and short bouts of minor shortness of of breath - no fever) starting with the shabbos after Purim, culminating with her deciding to get tested on 3/20. I had some very minor cold like symptoms that week, but then had fever for a few days after that, which was enough to make me retreat to bed for a day or two. So whatever happened to both of us was basically contained to March, with both of us feeling completely symptom free by April. We did our antibody tests on 5/4, so we're talking about more than a month symptom free.
A) You caught it once she was contagious, so you tested yourself too early because you’re really 2 weeks behind her
Similar to
@etech0 comment. Given our timeline, I don't see how this could be the explanation.
B) She had a low viral load, not enough to really infect others so you didn’t catch it from her
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@yeshivabucher comment. It's an interesting idea, and I've heard the level of viral load being discussed in terms of people getting infected, but nothing about it in regards to the contagiousness of the already infected individual. I'd be curious to see more discussion of this with all the research going on.
C) Not everybody gets it from everyone, as long as she didn’t sneeze or cough close to your mouth/nose it’s possible for you not to have gotten it but still get it from any random person who sneezes
Always a possibility, but like I said before, I know for myself that it was ain lecha exposure gadol mizeh.
D) You have some type of natural immunity so your body didn’t need to produce antibodies and you didn’t show symptoms
I haven't seen any discussion of such a concept. How would it even work? What natural properties/characteristics could possible provide immunity?
E) You got it, but in a really small dose, so it didn’t show on a test and you didn’t produce antibodies
This could be as well, but practically speaking, I assume it would put me in the same boat as not having had it at all.