COVID-19's Big Fat Non-Surprise
"A Covid Mystery" proclaimed a New York Times newsletter. "Why has the death toll been relatively low across much of Africa and Asia?" Like a know-it-all kid in 7th grade, I thought: "Call on me! I know this!" and clicked on the item. But to my surprise, the account that followed completely failed to mention what I thought was the obvious answer.
David Leonhardt's piece notes the fact that, against all expectations dating from the early stages of this pandemic, poorer countries of Africa and Asia have suffered only a small fraction of the death rates from the coronavirus that wealthier nations have experienced. In the U.S., we've had 1,580 deaths per million inhabitants. Italy has had 1,651, whereas Egypt has had 109, and Nigeria 10.
Leonhardt lists some potential causes for this unexpected result. Could it be that poorer countries have younger populations? They do. But that doesn't quite account for the disparity.
Another potential cause of the differential: It's possible that people in Africa and Asia have had exposure to similar pathogens in the past and that their immune systems were primed for COVID-19.
Some countries' leaders responded better than others to the pandemic. But that doesn't solve the puzzle either, writes Leonhardt, since many of the nations with low death tolls have had government responses that have been as weak and scattershot as countries with higher mortality.
Leonhardt closes by concluding that multiple factors must be a work. That is almost certainly right, and yet, there is one factor he failed to take into account.
Pulitzer prize-winning writer and cancer specialist Siddhartha Mukherjee addresses the same subject in the New Yorker, concluding that, "For many statisticians, virologists, and public-health experts, the regional disparities in COVID-19 mortality represent the greatest conundrum of the pandemic."
This seems odd because just last week, the World Obesity Federation issued a report showing that there is a clear link between excess body weight, especially obesity and COVID-19 mortality. Overweight was more predictive of severe COVID-19 illness than any factor with the exception of age. They found that in countries where less than half the adult population was classified as overweight, the risk of death from the coronavirus was about one-tenth the level found in nations where more than half are overweight or obese.
People who are overweight or obese are more likely to get severely ill and to die of COVID-19 even after controlling for factors such as sex, ethnicity and income.
In his New Yorker piece puzzling about international disparities, Murkerjee raises the examples of Mexico and India, noting that they are quite close in age distribution, yet India's death rate is only about one-tenth of Mexico's. He continues: "So perhaps other populational features are significant. Take, for instance, the structure of an individual family and its living arrangements: who cohabitates with whom?"