- Also... Archived Message
Posted by Rich
on April 29, 2020, 10:33 am, in reply to "Re: Coming Out of Lockdown Unprepared"
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1.10 Collective immunity requires good individual immunity. One of the implications of the high basic reproduction rate R0 of COVID-19 is that a large proportion of the population must be well immunized individually to ensure collective immunity, namely 85% for an R0 ~ 7 https://tinyurl.com/srmx5fd, https://tinyurl.com/sjjfpdn, https://tinyurl.com/ycgu3qgm. As natural immunity depends on the quantity of antibodies present, it seems unlikely that the 85% of effective individual immunity necessary for collective immunity can be reached when 30% of the population has little or no anti-COVID-19 antibody. An R0 ~ 7 is the largest estimate in the literature, chosen according to the precautionary principle. Even with a value of only 4 for R0, 75% effective individual immunity would be required. It seems clear that collective immunity cannot be relied on to stop the spread of COVID-19 when the individual level of antibody is often low and when a high level of antibody is associated with an exacerbation of the disease. |