Fascinating insights in this video. Well worth watching, maybe even important to watch. You can fast forward through it, if you wish, to get the gist of the message.
Several studies have published estimated IFRs for various regions around the world. For those below age 70, the IFRs are much lower than the overall/all age population IFR. Another study Dr Campbell shows us finds a strong correlation with age demographics as the factor that distinguishes a low IFR in one region with a high IFR in another. 90% of the difference can be explained by population age differences.
He then shows population pyramids of different countries including a couple in Africa, where disease prevalence is low. The implication is that its low there because overall life expectancy was already low (unfortunately) – and hence, their population is massively skewed towards young people with very few older people. Cases in Kenya have been mild and asymptomatic with few deaths (less than 600 for a population of over 50 million). By comparison, California has had about 17,000 deaths with a population of almost 40 million.
The take aways from this video are many, but the interpretation is left up to you.
Do not confuse case fatality rate (CFR) with infection fatality rate (IFR).