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A New Understanding of Herd Immunity
- SlipperySlope 6y agoEssentially, deaths in NYC are way down because the people there who mingle unsafely have already achieved herd immunity. Evidently 25% of the NYC population infected was enough. Suppose NYC population for COVID statistics is 8.5 million. NYC reports 22795 COVID deaths. With 25% of 8.5 million having COVID antibodies, that means 2.1 million infected. The case fatality rate in NYC thus computes to 1%. Projecting to current hotspots, this analysis suggests that with triple the NYC population, Florida will need 60 thousand or so total COVID deaths to achieve herd immunity to the extent of the analogy between NYC and Florida.
- keypusher 6y ago> Models like Britton’s and Gomes’s also assume that, after infection, people obtain immunity. There is growing evidence that people can catch covid more than once, even within a short time after clearing the first infection. While not 100% proven yet, if true it would basically throw herd immunity out the window until there is an effective vaccine. https://www.vox.com/2020/7/12/21321653/getting-covid-19-twic.. https://www.vox.com/2020/7/12/21321653/getting-covid-19-twic....
- occamrazor 6y ago> 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. A paragraph below in the article.
- keypusher 6y agoI linked a clear instance of exactly that, an article written this week by a doctor whose patient contracted the virus twice in a short period, with references to other examples. Further, the claim that most viruses create immunity for a meaningful length of time is questionable. > repeat infections in a short period are a feature of many viruses, including other coronaviruses