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Beware Drawing Parallels Between Smallpox and Covid-19

Much of this letter relies on Jay Bhattacharya’s and my op-ed in the August 5th, 2021, edition of the Wall Street Journal.

Editor, Los Angeles Times


Saad Omer concludes his op-ed on the surge of omicron in China by praising the U.S.’s and U.S.S.R.’s earlier joint effort to eradicate smallpox (“China’s lockdowns are a warning to us all,” March 18). As admirable as was this effort to eradicate a deadly disease, we must beware of drawing too many parallels between smallpox and Covid-19.

Smallpox was dozens of times more deadly than are earlier strains of the SARS-CoV-2 virus. Because omicron is less deadly than are earlier Covid strains, the huge gulf separating the lethality of smallpox from that of omicron is even larger. Another notable difference is that smallpox killed children in droves, while Covid is disproportionately dangerous to the elderly while posing almost no danger whatsoever to children – and hardly any danger to young adults.

Also, unlike SARS-CoV-2 which uses as reservoirs animals in addition to humans, smallpox used only humans. This reality helps explain why smallpox is only one of two contagious diseases that humans have deliberately eradicated – the other being rinderpest, which affected only even-toed ungulates.

Finally, it’s worthwhile to recall the wisdom of the late epidemiologist Donald Henderson, who’s credited with playing a key role in smallpox’s eradication. In a 2006 article, Henderson, et al., counseled careful thinking about disease-mitigation measures such as “travel restrictions, prohibition of social gatherings, school closures, maintaining personal distance, and the use of masks.” The authors conclude:

Experience has shown that communities faced with epidemics or other adverse events respond best and with the least anxiety when the normal social functioning of the community is least disrupted. Strong political and public health leadership to provide reassurance and to ensure that needed medical care services are provided are critical elements. If either is seen to be less than optimal, a manageable epidemic could move toward catastrophe.

Donald J. Boudreaux
Professor of Economics
Martha and Nelson Getchell Chair for the Study of Free Market Capitalism at the Mercatus Center
George Mason University
Fairfax, VA 22030