I read this board just about every day and don't remember seeing multiple posts of reinfection. What I do remember reading is that people who had it (or "are pretty sure they had it") still need to be cautious because we aren't sure about the long-term immunity situation. That said, the research is promising that so few show evidence of reinfections.

Herd immunity is real, but with the number of travelers, not to mention births, it's not clear it is achievable unless it rips through the entire world.