Just a few words about the coronavirus. Clearly, the Internet is in need of my contribution to this topic.

You might’ve noticed this: whenever there is a discussion about the coronavirus, some dolt appears out of nowhere and says something along the lines of “to put things in perspective, some 450K people died this year of flu”.

The number is accurate, but the implication that the coronavirus situation is overhyped is completely wrong.

Currently, the WHO estimates this coronavirus (SARS-CoV-2) to have mortality rate of 3.4% (the 1918 “Spanish flu” had mortality rate of 2.5%). So if you really want to put things in perspective, the average mortality rate of seasonal flu is less than 0.1%.

Yes, the coronavirus is at least 34 times more deadly than the flu and already killed more people than SARS (mortality rate 10%) and MERS (37%) put together.

There are two basic reasons for this. First, in many cases the infection presents as mild or asymptomatic. This means there are a lot of infected people going about their business, having no idea they carry the virus and may be contagious. There may be nothing about their appearance that would raise any red flags. Healthcare here in the US is expensive to say the least. Many people will not seek medical help even if they experience some symptoms, making a bad situation worse.

Second, SARS-CoV-2 has a very high reproduction number (R0) that denotes the average number of people who will catch a disease from one contagious person. For as long as R0 > 1, the virus will spread, causing an epidemic or a pandemic.

The WHO currently estimates SARS-CoV-2’s R0 at 1.4 – 2.5. This is a very high range and this estimate is one of the most conservative. The Chinese researchers estimated R0 for this coronavirus at 3.3 – 5.5, while a similar study in the US placed R0 in the 3.6–4.0 range.

The median R0 for seasonal flu – the one that kills half a million (give or take a hundred thousand or so) people worldwide every year – is less than 1.

Even if we look at the most severe flu pandemics in recent history, SARS-CoV-2 beats them all in both transmissibility and mortality rate:

  • 1918 flu pandemic (“Spanish flu”): median R0 1.80; case fatality rate 2.5%; killed 17-50 million people. This number may be as high as 100 million. That’s about how many people died in WWII from all war-related causes. Talk about putting things in perspective.
  • 1957 flu pandemic (“Asian flu”): median R0 1.65; case fatality rate 0.2%; killed 1 – 1.5 million people, including 70,000 in the US.
  • 1968 flu pandemic (“Hong Kong flu”): median R0 1.80; case fatality rate 0.01-0.08%; killed 1 million people, including about 34,000 in the US.
  • 2009 flu pandemic (“swine flu”):  median R0 1.46; case fatality rate 0.01-0.08%; killed 150,000–575,000 people.

SARS-CoV-2 has a potential to kill tens of millions of people worldwide. With the recent flu pandemics, deaths in the US were around 4% of global casualties. Considering that the US has about 4.25% of global population, well, we’re nothing special in terms of our ability to deal with such pandemics.

This means that, if SARS-CoV-2 kills 50 million worldwide like the “Spanish flu” did, two million of those dead will be us. Still think the coronavirus situation is overhyped? Go wash your hands.

For your reading pleasure

J. Chen, “Pathogenicity and transmissibility of 2019-nCoV-A quick overview and comparison with other emerging viruses,” Microbes and Infection, 04-Feb-2020. [Online]. Available: https://www.sciencedirect.com/science/article/pii/S1286457920300265#bib12. [Accessed: 05-Mar-2020]

Biggerstaff, M., Cauchemez, S., Reed, C., Gambhir, M. and Finelli, L. (2020). Estimates of the reproduction number for seasonal, pandemic, and zoonotic influenza: a systematic review of the literature. Available: https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-14-480 [Accessed: 05-Mar-2020]