This news could have some concerning implications, but there are also still some plausible, less gloomy scenarios. Some of the details from the Times article wo

This news could have some concerning implications, but there are also still some plausible, less gloomy scenarios. Some of the details from the Times article worth noting: the man's symptoms during the initial infection were mild, and in the most recent case, he has had no symptoms. This is notable because there have been several conflicting studies measuring the potential immune response of low severity Covid19 infections, with some showing that antibody and T-cell responses are strong, and others showing that they are weak. This means that potentially, mild cases of Covid will not produce long-lasting protective immunity for some. Additionally, the fact that he fails to show symptoms currently could be an indication that while immunity may not completely prevent reinfection, it may reduce severity. It's been hypothesized that many diseases, including the flu and the common cold, were more deadly upon their initial introduction to the population and, over time, as people gained stronger immune responses from exposure, became less lethal. Additionally, flu vaccines, even if they don't prevent the flu completely, can reduce the severity of the illness. Its possible that this is evidence that, even if it is not possible to completely immunize the population against Covid19, widespread vaccination and infection will lead to it may simply become another endemic, relatively low-severity disease along with the common cold/flu/etc. Of course, this is all based on literally a single patient, so at this point anything is still possible.