HOPEFULLY it's fine and this won't be A Thing https://www.sciencemediacentre.org/expert-reaction-to-people-being-re-tested-positive-for-coronavirus-after-initial-recovery-e-g-case-reported-in-japan-where-a-woman-has-been-confirmed-as-a-coronavirus-case-for-2nd-time/Assuming that there is a minimal possibility of misdiagnosis, it still remains unclear from the published reports whether the person involved was likely re-infected, or whether this represents an infection that may have been partially cleared or perhaps has gone latent. In either case, given the number of reported cases thus far, it would seem unlikely that this is a common occurrence, and thus should have only a small impact on the overall epidemic projections themselves. Of possibly greater concern are the implications for control measures – should quarantine periods be extended? It also makes contact tracing even more difficult, potentially straining resources.
It tracks, though. Presume our model says R0 is 2.2. LANL says R0 is between 4.7 and 6.6 - one way to square those two results is to presume a plurality of cases are asymptomatic. An R0 of 2.2 with mysteriously unknown spread could look a lot like an R0 of 4.7 for a highly asymptomatic, biphasic illness. So. You're gonna get it, you might not even know, and it's extremely unlikely to kill you. But if you do, it'll be the flu. I mean, it responds to Tamiflu. From a lay perspective it's basically gonna be a really shitty flu season... which means if you're in a population that needs to worry a lot about the flu, you should be worried.