Since the early days of the current pandemic, the go-to comparison has been influenza, both the specific historical outbreaks and the general seasonal “flus” (a catch-all term for respiratory viruses) which hit all over the world every winter.
That comparison is very often met with this simple retort:
Covid is nothing like the flu, it’s 20 times more dangerous!”
But is this true?
No, it’s not.
While the generally accepted flu death rate of 0.1% is twenty times lower than the media reported Covid19 death rate of between 2% and 4%, research suggests the media-reported death rate is far too high.
The World Health Organization has estimated Covid19’s “official” death rate at 3.4%, clinical studies done on Sars-Cov-2 put its actual case-fatality ratio at around 0.1%. Roughly equal that of regular season flu outbreaks.
The problem arises from what scientists and statisticians call “selection bias”:
the bias introduced by the selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative
Essentially, the way you choose your sample can have a huge impact on the results of your study.
In this case, since only the people sick enough to need treatment in hospitals or clinics are being tested, only those people with severe or critical symptoms will ever be counted in the statistics.
The WHO figure, for example, of 3.4% is based only on those patients who were treated in hospital.
But what about people who got sick but never reported it? Or who never had any symptoms so never knew they were infected?
Accounting for these cases brings the death rate down by a factor of ten.
The countries that have done the broadest population studies – ie. testing random sections of the population who have no symptoms – are Germany, South Korea and Iceland.
These are both, potentially, markedly LOWER than seasonal flu.
In short: No, coronavirus is not “20x deadlier” than the flu. The science suggests it may be anything from very slightly worse, to noticeably better.