April 20, 2020
As General Turgidson said in the War Room in Dr Strangelove, “…Although I hate to judge before all the facts are in, it’s beginning to look like General Ripper exceeded his authority.”
Maybe the same is true of some of the computer modeling being used by politicians to direct their decisions in this recent unpleasantness? Maybe not. The science journal Nature reports: Antibody tests suggest that coronavirus infections vastly exceed official counts. The Nature article refers to the Santa Clara county study in California published in medRxiv
The testing involved a test for Covid-19 antibodies in the blood of the local population, a random sample of which was selected for the study. In the paper the authors say:
…A combination of both data sources provides us with a
combined sensitivity of 80.3% (95 CI 72.1-87.0%) and a specificity of 99.5% (95 CI 98.3-99.9%).
That’s a pretty good specificity.
…We conclude that based on seroprevalence sampling of a large regional population, the prevalence of SARS-CoV-2 antibodies in Santa Clara County was between 2.49% and 4.16% by early April. While this prevalence may be far smaller than the theoretical final size of the epidemic, it suggests that the number of infections is 50–85-fold larger than the number of cases currently detected in Santa Clara County.
If true, this is huge. Why? Because a vast number of people may have encountered the virus, been infected, developed antibodies, and never gotten ill, which means that many more people are now immune than has been supposed. The only way to settle this is for all regions to carry out significant randomized sampling for the antibodies. Everyone seems to be behind the curve on that one.
In terms of projections, the School of Public Health at Georgia State University, has online a set of interactive graphs tracing the projected cases at various times with the actual data illustrating how the projections change all the time. It should impress one thing on everyone’s minds–data are real, projections are not.
Short memo today; interrupted by online cocktail party.
Rebel Yell
PS Interview with Swedish epidemiologist; Why the lockdown approach is a waste of time and counterproductive….