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Odds and Ends
7 5, 2:33am
Basic level being the genetics of the virus.
The antibodies usually targets strains of a virus, not the virus itself, its why some viruses you can't develop immunity against by getting sick, because they mutate.
You are right, there are speculations that the reportet cases could be just that, or simply bad tests... However it is not unheard of that you can get sick of the basic same virus again later (the flue normally being the used example). Thing is, we are hearing about such cases from both China, South Korea, Taiwan and Vietnam, making it much more likely that it has mutated in those areas and spread again.
I don't know what is the case (and I suspect that you don't either), but I do know that vaccines can be made to target the virus even if it has to be issued every season, meaning we can get on with the daily life much more safely.