The Great Barrington Declaration, COVID-19 and Herd Immunity

One of the problems with DIY Science is that an awful lot of people use terms of art incorrectly. The term “herd immunity” is one such term. It refers to a point of steady state equilibrium. In essence, a sufficient proportion of the population has been infected and retains sufficient immunity such that it shields most of the rest of the population from infection. 

This does not mean that the virus is eradicated. Nor does it imply stasis. People who got infected can and probably will be infected again. That is the pattern of other corona viruses, for instance, the flu. But the body’s defenses build up and the virus weakens over time, consequently reducing the severity of subsequent infections, until such time as the immune system weakens with age. That is why the sensible course of action is to take steps to develop effective therapeutics and protect vulnerable populations, particularly the elderly. 

That said, there should be no illusion that COVID-19 is going to be eradicated. The only virus in the world that has been successfully eradicated is smallpox. All the rest are still with us and contained by the use of vaccines, proper sanitation (like clean water) and other public health measures. Parenthetically, it should be noted that vaccines, which are often only 50% effective, are but one tool in the arsenal whose function is to contain the virus and treat patients. Eradication is not likely to be in the cards. 

It is important to consider another factor, namely that the infection estimates that are published daily in the U.S. are very likely incorrect, perhaps by an order of magnitude. Various studies have shown that actual infections far outnumber confirmed infections, possibly by as much as 6 to 24 times the amount. See for instance, this article in Reason Magazine and this column by Holman W. Jenkins in the Wall Street Journal

It is unfortunate that coverage of the Coronavirus pandemic has verged on the hysterical. Why is an interesting question. It is clear that many journalists writing about the virus have no understanding of science. They do not understand the distinction between a data point and a sample; nor do they understand the basics of research design or statistical methodology. Nor have many read, much less understood, the research papers they cite.  

But it is vitally important to understand the nature of the virus and the policy implications for dealing with it. That means understanding the costs, benefits and trade-offs needed to contain and treat it. The authors of the Great Barrington Declaration have provided a framework for doing just that. Below is an interview with Oxford Professor Sunetra Gupta, one of the authors of the Declaration. It is well worth watching. 

Professor Sunetra Gupta