No, and there have been at least three reports of reinfection cases from multiple countries.
Though it's not clear if they failed to build immunity or if the virus was never totally eliminated.
Also, because of antibody dependent enhancement (ADE), which the virus is speculated to have like SARS and MERS, a reinfection could be deadly, e.g. triggering cytokene storms. This is why vaccine trials in animals failed for SARS and I think MERS.
Not a doctor here, but I also read that people can test negative when tested orally but still test positive anally. Three cases sounds a little anecdotal. Let's brings some facts into the discussion.
Though it's not clear if they failed to build immunity or if the virus was never totally eliminated.
Also, because of antibody dependent enhancement (ADE), which the virus is speculated to have like SARS and MERS, a reinfection could be deadly, e.g. triggering cytokene storms. This is why vaccine trials in animals failed for SARS and I think MERS.