Was I in the wrong in this situation?

My sister (who lives with me and my mom) decided to go to her friend's house on Sunday and is still there. Her friend's boyfriend, who lives in a place with several cases of COVID19, went into the hospital with a lung infection.

I told my mom (she is 60 and was a lifetime smoker so she would be particularly vulnerable to COVID19). I didn't say he had COVID19, but that he simply had a lung infection.

My sister is mad at me & said she's never telling me anything ever again because I can't be trusted. But when she told me, she didn't even tell me not to tell my mom. It is not like she confided some deep secret & I went around telling people.

Was I in the wrong for telling my mom? (Btw as an update, my friend's boyfriend got tested & luckily he just has strep throat, not COVID19).
Was I in the wrong in this situation?
I didn't read
Vote A
I read, but have no opinion
Vote B
It was right to tell your mom
Vote C
It was neither right nor wrong to tell your mom
Vote D
It was wrong to tell your mom because you violated your sister's trust (even though she didn't tell you not to tell her)
Vote E
It was wrong to tell your mom, for another reason
Vote F
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1 y
She keeps making me out to seem like the bad guy & that I need to pay her back somehow. You guys gave me the confidence that I was right in what I did, so I defended myself. I said "with a 60 year old mother who's been a lifelong smoker (which puts her more at risk for covid19) you really shouldn't have been hanging out at the house of someone who lived in a place where there are over a thousand cases of covid19".

She blocked me. Whatever.
1 y
She just unblocked me & tried to message me again, but I just blocked her back as revenge because I'm petty LMAO
1 y
He actually did have COVID19. He got an antibody test and it came back positive. Apparently the original COVID19 test was inconclusive or something. At least that's what they tell me; they've admitted to lying to me about a lot of things.
1 y
My sister's friend tested positive for COVID19 antibodies. Turns out I was right to not want them in the house for a couple weeks
Was I in the wrong in this situation?
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