Re:Covid-19 Antibody Seroprevalence in Santa Clara County, C...
by fiftyfifty on Friday April 17, 2020 @03:02PM
(#22901875)
What percentage of immunity can we expect to see a slowdown in the spread of the disease? While we may need 60% or more to achieve full herd immunity surely somewhere lower than that we can expect to see a noticeable reduction in the spread?
Re:Covid-19 Antibody Seroprevalence in Santa Clara County, C...
by ignoramous on Friday April 17, 2020 @04:02PM
(#22902446)
> ...noticeable reduction in the spread?
I believe the SIR model [0] answers those questions. 3blue1brown's video on the topic is super digestible and informative [1].
In short, the discovery of a prophylactic if not a therapeutic treatment are our best immediate bets, absent which, quarantines and lockdowns will have to persist to curb the spread of a disease as infectious as covid-19 whilst we patiently wait for an effective vaccine against it [2].
[0] https://en.wikipedia.org/wiki/Compartmental_models_in_epidem...
Yes and no.
A disease is endemic when R0 x S = 1 [0]. R0 for SARS-CoV-2 is estimated to be 2.5 to 3.5 and some models predicting a much higher 5.7 [1].
The herd immunity threshold is given by (1 - S)%, which implies when R0 = 2.5, 60% of the population would need to be immune; similarly 71.42% and 82.45% for R0s, 3.5 and 5.7, respectively.
[0] https://en.wikipedia.org/wiki/Endemic_(epidemiology)
[1] https://news.ycombinator.com/item?id=22817942