A study was done by Stanford looking at the prevalence of COVID-19 in Santa Clara County CA. It's available as a pre-print here:
https://www.medrxiv.org/content/10.1101/2020.04.14.20062463v1.full.pdf
The sampling is questionable (volunteers solicited through Facebook advertising), but they attempt to correct for demographics with weighting. Uncertainty is large, but it suggests the prevalence of COVID-19 was 50-85 times that confirmed with testing.
Certainly would like to see more and better data, but this suggests that COVID-19 is statistically less lethal for the individual infected (something akin to a very aggressive influenza, which is dangerous enough to susceptible populations), but due to its contagiousness it makes it more likely to spread, thus causing the increased numbers of deaths.
The CDC published an estimated R0 of 5.7, which indicates that herd immunity cannot be achieved until more than 82% of the population is immunized through infection or vaccination.
https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article
https://www.medrxiv.org/content/10.1101/2020.04.14.20062463v1.full.pdf
The sampling is questionable (volunteers solicited through Facebook advertising), but they attempt to correct for demographics with weighting. Uncertainty is large, but it suggests the prevalence of COVID-19 was 50-85 times that confirmed with testing.
Certainly would like to see more and better data, but this suggests that COVID-19 is statistically less lethal for the individual infected (something akin to a very aggressive influenza, which is dangerous enough to susceptible populations), but due to its contagiousness it makes it more likely to spread, thus causing the increased numbers of deaths.
The CDC published an estimated R0 of 5.7, which indicates that herd immunity cannot be achieved until more than 82% of the population is immunized through infection or vaccination.
https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article