If you weren’t depressed enough, a new study suggests that post-infection immunity to SARS-CoV-2 could be lost within months.
Blood tests revealed that while 60% of people marshalled a “potent” antibody response at the height of their battle with the virus, only 17% retained the same potency three months later. Antibody levels fell as much as 23-fold over the period. In some cases, they became undetectable.
Interesting news to drop right before James Hamblin’s discussion of various herd immunity models, wherein he issues this caveat.
Models like Britton’s and Gomes’s also assume that, after infection, people obtain immunity. This is a clear caveat that all the researchers make. COVID-19 is a new disease, so no one can be sure that infected people become immune reliably, or how long immunity lasts. But Britton noted that there are no clear instances of double infections so far, which suggests that this virus creates immunity for at least some meaningful length of time, as most viruses do.
It’s getting to be time we start thinking of the coronavirus as the setting, not the story.