• It is the first confirmed case of a U.S. patient becoming re-infected with Covid-19, and the fifth known case reported worldwide.
• The resident of Washoe County, Nevada, who had no known immune disorders or history of significant underlying conditions, required hospital treatment on testing positive for Covid-19 for the second time.

Also see:

Reinfection cases raise concerns over immunity

https://www.reuters.com/article/us-health-coronavirus-reinfection-usa/covid-19-again-reinfection-cases-raise-concerns-over-immunity-idUSKBN26Y1FA

• He has now recovered, though the case raises further questions about the prospect of developing protective immunity against the coronavirus. ...