Coronavirus has long been said to target the elderly, but systematic data over large populations and geographical areas are only now becoming available. An article published earlier this month in the European Journal of Epidemiology found that age and fatality rate are exponentially related in SARS-CoV-2 infections.
The fatality rate study was based on data from Belgium, England, France, Ireland, Italy, Holland, Portugal, Spain, Sweden and Geneva, Switzerland, plus 11 US states as well as the results of comprehensive testing and tracing programs in Australia, Iceland, Korea, Lithuania, and New Zealand.
Based on these figures, the authors concluded that the case fatality rate for children, and even adults in their 20s, is very low. There is an 0.002% fatality rate for 10 year-olds and a 0.01% fatality rate for 25 year-olds. As seems logical, these groups also experience “fewer and milder symptoms,” the study found.
However, the fatality rate rises exponentially to 0.4% at age 55, 1.4% at age 65, 4.6% at age 75, and 15% at age 85. There is little point, therefore, in talking about “the fatality rate” of Covid-19.
The study authors subsequently conclude that much of the difference in Covid-19 fatality rates between geographic areas is due to the age distribution within populations. A further crucial factor is the implementation of measures to protect the elderly from exposure to the virus.
Case fatality rates have been notoriously variable and difficult to determine since the start of the pandemic. In New York City, Covid-19 fatalities at one stage represented 10% of reported cases, but large-scale seroprevalence studies found the real total number of infected persons as ten times higher than the reported case figures.
This only serves to confirm that there are many people carrying, and probably transmitting, the SARS-CoV-2 virus who never become sick or even aware of their infection. Given the above fatality rate data – and the tendency for children to also be less likely to have noticeable symptoms – it may well be that although the elderly are the ultimate victims of Covid-19, it is younger people who predominately transmit the virus.