Chances of being reinfected immediately?

[RockingMyFiftiesNot]

Ok so I know nobody can really say but it's a 'what are the chances' question, following on from a phone call with a friend last night.

She is pretty certain she picked up covid on a recent business trip (timing works, hadn't been anywhere else etc)Her DP came down with symptoms and tested positive a few days later. He also hadn't been anywhere else so almost certainly caught it from her.

She is now negative, he is still positive and she asked me whether i thought she could become reinfected from him. I could only say I don't know, although would expect her immunity to have had a good boost.

As said, I don't expect anyone to know the answer to this categorically but I've been mulling it over since she asked and would be interested in others' thoughts.

Back in the old days when there was guidance about isolating as a contact, one family member testing positive a few days after the first would be considered as part of the same "episode", so would mean that the original person who was the likely source of infection wouldn't then need to re-isolate once they had recovered from COVID. If it's the same infection (ie she infected him with it) then no, she wouldn't be reinfected by the same infection.

If it’s the same strain I would imagine the chance would be very low if not zero. That’s not to say she couldn’t catch it again from someone else very soon, as from what I’ve read, the latest variants don’t offer a great deal of immunity post infection. But if she gave it her DH, then no, I don’t think she could get reinfected (or the change would be minuscule)

Thank you both, that's the conclusion she and I drew. Time will tell I guess!