I don't think there is any evidence of reinfection. What seems to have happened in some cases is that a person's symptoms have dissipated but resurfaced a bit later. In other words, the patient thought they had recovered when they hadn't.

That said, the chief scientific officer has stated that this is likely to be an annual virus: https://www.telegraph.co.uk/news/2020/03/13/coronavirus-outb...

I had the same discussion a few days ago and someone posted https://www.businessinsider.com/wuhan-coronavirus-risk-of-re... [It has a link to a video, but the caption of the video is wrong. The recommendation to the cured patients is not to increasing their physical activity but to enhance their own health safeguards.]

I found two other articles about the same case https://globalnews.ca/news/6623287/coronavirus-multiple-infe... and https://www.reuters.com/article/us-china-health-japan/japane... . t's not 100% clear, but it looks like a continuation of the first infection after a few week of no symptoms. It makes more sense than no immunity (at least at the short time), and a second independent infection.