Yes... in the early days of COVID in the U.S. there were most likely 9 infections for every detected case. This is back in days where COVID testing was not widely available and many people could not get a COVID test. In recent months there are most likely 3 infections for each detected case. This is all backed by data that looked at infection level including the analysis of sewage waste from cities/towns, antibody sample testing & other methods to detect COVID infection level. The people who had asymptomatic infections also was a factor in infections not being detected for cases -- since if you don't feel sick it is unlikely you would go for a test.
These are the facts which yields the 2% Case Fatality Rate in the U.S. --- but an estimated 0.55% Infection Fatality Rate in the U.S. (figures all pre-vaccine). The cases are known but the number of COVID infections only estimated.
Now let's re-visit again where the U.S. is at on herd immunity.
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Taken from an earlier post on April 12th - https://www.elitetrader.com/et/threads/the-biden-covid-vaccine.352858/page-31#post-5363566
Let's walk through some basic math. Even when 50% of the U.S. adult population achieves full vaccination we are still nowhere near herd immunity. 255 Million people in the U.S. population are 18 and older (2019) out of our 328 Million population. This is 77.7% of our population. If 50% of the U.S. adult population is vaccinated; this means that 38.8% of the U.S. population is vaccinated for a total of 127.5 Million people vaccinated.
However we need to take in account the percentage of the adult population who have lasting natural herd immunity from catching COVID. The U.S. has experienced 32 Million COVID cases. For each proven case there appears to be 3 infections that were not caught with testing. This implies the U.S. has experienced 128 Million cases. Of these (following population distribution) 99.5 million were in adults 18 and over.
Studies have shown that only 60% of people who caught COVID have antibody levels which provide immunity after 6 months. This means that 40% of people who caught COVID are not immune. This implies that only 76.8 Million of the people who caught COVID would have natural herd immunity in the U.S.
However the accounting does not stop here; approximately 50% of the adults who previously got COVID have also been vaccinated. This means that (99.5 million adults * 60% effective * 50% got vaccinated) = 29.9 million adults must be subtracted from the "natural immunity" total since they actually are on the vaccinated list. This leaves 76.8 million minus 29.9 million people for a total of 46.9 million people in the U.S. have natural immunity which will last longer than 6 months.
This means that 127.5 Million adults are vaccinated plus 46.9 million people with natural immunity (not on the vaccination list). This gives 174.4 Million people in the U.S. with immunity not accounting for that vaccines only have 78% to 95% efficacy.
Herd immunity for COVID will require 70% of the population (229.6 Million people) to have immunity at minimum. We currently are only at 174.4 Million people (53.2%). We are making progress but there is further to go. Also there is a concern that herd immunity for a population will require closer to 85% of a population for COVID rather than 70%.
Of course this calculation does not even consider that vaccines are less effective against COVID variants and that some people who caught COVID may not immune against most variants leading to re-infections.
So the bottom line - get vaccinated to help the U.S. reach herd immunity, get back to normal, and stop further sickness across society. We still need more people to get vaccinated to achieve the necessary herd immunity levels -- the sooner the better.
