And it takes a few weeks after that second shot for full immunity to kick in. My vaccine details said two weeks after the second does for maximum immunity, but Moderna might be different.

And even then no vaccine is 100% effective in each and every individual. Without pre-vaccine tests it is also impossible to say whether or not a patient was already infected before getting the shot.

not true, the 2nd shot is for long-term immunity

tho the vaccination was less than ten days in the past, so it might not have been active yet

You are right, it seems that a lot of people develop antibodies after the first vaccine.

source: https://www.bbc.com/future/article/20210114-covid-19-how-eff...

I can’t explain it either, just that it was confirmed in both cases by medical staff. She is pregnant, so they are extra careful.