Here is a non-expert, conservative writer who makes a good case that obesity is the cause of varying death rates in different countries. There are few deaths in Africa not because they use one drug or another, or genetics, but because obesity is rare.
https://thebulwark.com/covid-19s-big-fat-non-surprise/
COVID-19’s Big Fat Non-Surprise
Tip-toeing around the linkage of coronavirus mortality and obesity doesn’t do anyone any favors.
. . . 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?”
But wait, do we need to ask that? The World Obesity Federation provides country-by-country breakdowns of overweight and obesity. According to their data, the percentage of India’s adult population categorized as obese is 3.9. In Mexico, it’s 28.9.