A recent op-ed piece in the Wall Street Journal claimed that the United States may be able to reach herd immunity from COVID-19 by the end of April. Is this reasonable? Some of the assumptions made in the op-ed piece were a little sporty, so I thought I would do my own independent cross-check. I’m am familiar with this process as part of my work as project managers tend to be optimistic and they have often tried to sell me on low cost estimates.
Speaking of optimistic, I’m going to make some optimistic assumptions myself to simplify my analysis and to get an early bound on the potential for her immunity. There are three factors we need for the estimate – the number of people who have already had COVID-19 in the U.S., the number of people who need to be immune to reach herd immunity, and a forecast of the number of people who will be fully vaccinated in the next few months due to vaccination.
The death rate from COVID-19 has been estimated as 0.6%. That is, 0.6% of people infected with COVID-19 die from the virus. About 547,000 people have died from the virus in the United States as of March 15th. From those two numbers, you can infer that 91 million in the U.S. have been infected at some point in the last year with the novel coronavirus. This is 27% of the 331 million people in the country.
This 27% figure is far below what is needed for her immunity, even if we assume everyone who has been infected and survived is now immune for the foreseeable future. Estimates of herd immunity range from 70-90%. We will assume 75% is needed for herd immunity – this may be reasonable for a return to normality if most of those not vaccinated are younger, healthier people who have demonstrated extremely low mortality rates from the novel coronavirus.
To achieve 75% herd immunity, we will assume that the only people who are getting vaccinated are those who have not been infected so far (although I know this is not a true assumption, this is an optimistic forecast and this assumption makes the analysis simpler). We would need 48% of the American population to get their second shot, and they would need another two weeks past that point to be fully immune.
Extrapolating from CDC data on second vaccine shots provided, we will likely reach the 48% threshold in mid-May. That’s a little later than the Wall Street Journal piece, and likely optimistic for the reasons I have cited. But it gives me hope we will be able to return to normality by the 4th of July holiday. In the mean time, we all still need to be careful and wear our masks.
A great look behind the COVID curtain, Christian! Thanks for sharing!
How are you accounting for the other deaths that were classified as COVID-19 deaths when they were for other causes such as heart attacks, cancer, gun shotgun, overdoses, and Diabetes? I know that when I went in for a post-surgery infection the hospital tried to change my admissions records to indicate that I had been diagnosed with COVID-19. I discovered this when I requested a copy of the medical records and was told that my request would be delayed because my admission records were being updated with my COVID-19 diagnoses. When I informed this individual that I did not have such a diagnosis, they immediately referred me to their supervisor who attempted to tell me the same thing and added that I much be mistaken because they were told to add this information from the hospitalist on my case. When I asked for this doctor’s name I was told that because of HIPPA they could not tell me this. A long story short, my investigation took my all the way to the hospital Administrator and it was their direction that all patients admitted just prior to the official announcement of the pandemic will be classified as a positive COVID-19 patient no matter the reason for the admission. This was so the hospital could bill for the extra care needs even though this extra care was never needed or given.
Thanks for your comment and sharing your experience. There are always errors in reporting, but when I look at the big picture, it seems to me that the deaths due to COVID-19 are significantly understated. The CDC publishes weekly death data in the U.S. and there was a 480k increase in 2020 from 2019. That is much more than the 360k official count for COVID-19 deaths (using Worldometer’s data).
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