How Many People Will Coronavirus Kill?

A million? 100 million?

As The Atlantic puts it, you are likely to get the coronavirus. According to leading epidemiologists, we are looking at more than half the world catching the disease. COVID-19 is no longer contained. The question now is what will it do?

The current estimate is that the disease kills around 2% of symptomatic cases. Multiply that by half the world and you get a lot of death (77 million to be exact), but it’s not that simple.

There are still enough unknowns that the death toll could range from 1-100 million. Hopefully less, but unlikely. If you watch Netflix’s Pandemic, the scientists often talk about the ‘big one’ that’s guaranteed to come. This is it.

What If It’s As Bad As The Flu?

The best case is that COVID-19 is like a bad flu season. The flu kills around 400,000 people every year, most of them 67 or older. It has an estimated mortality rate of 0.1%. So far this novel coronavirus is 20x more deadly, but perhaps we’re undercounting asymptomatic cases, or we’ll manage treatment better. If it kills just 0.1% of the infected, how many people would that be?

This graph lets you see the number of dead at different rates of infection. If 60% of the world is infected, as Prof Gabriel Leung has said, then we’re looking at over 5 million deaths. Even if we manage to contain this to swine flu levels, we’re still looking at 1–2 million deaths.

This seems crazy, unless you remember that the flu is killing nearly half that on the regular. This is basically our best-case scenario. A double flu season, which could also keep coming back until we develop a vaccine.

What If It’s Worse?

So far, however, this novel coronavirus seems much more deadly than the flu. The general estimate is 2%, and this graph lets you see the death count around that range (from 1% to 3%). As you can see, it gets pretty bad.

If the death-rate is 1% and 60% of the world is infected, we’re looking at 46 million deaths. This is as bad as the Spanish Flu, which was worse than World War I.

If the death-rate is 2%, we’re looking at nearly 92 million dead. That’s worse than WWI and WWII combined. Essentially, World War III.

The hope is that the mortality rate will actually be lower, because lots of people are asymptomatic. That seems likely, but still unknown. Even 1% mortality is a world of pain.

Can’t We Contain It?

All of these numbers depend on multiplying by some percent of the global population. What if we just keep the infection rate below 10%? Then this graph doesn’t matter at all.

The trouble is the growth rate. There was a very small window in November or December to contain this thing in Wuhan. Now it’s gone to major Chinese cities, to South Korea, to Iran, etc. Many virologists are saying that containment is no longer relevant. The cat is out of the bag, and it’s running.

This GIF cut from a video from Abacaba shows the growth rates of various viruses. As you can see, COVID-19 looks pretty quiet until around day 20, when it goes ‘viral’. Where the GIF cuts off, you can see the 2009 Swine Flu begin to take off. That disease eventually infected 10–20% of the global population. Luckily, its fatality rate was 0.01–0.08%, less than the flu.

If this coronavirus spreads to the same population with 40x the mortality rate, you can see that we have a 40 times bigger problem.

Who Will Die?

China CDC

The mortality rate of 2% is an average. The average person is actually relatively safe, because COVID-19 preys on the old.

In a recent study from the Chinese CDC, people over 80 had a 14.8% mortality rate compared to 0.2% if you were below 40. If you have children it is especially reassuring, because for them it seems not too much worse than the flu.

Those most at risk are the elderly and those already in bad health. Basically, US Presidential candidates should be worried about death, the US population not as much. But still. For anyone, this is rolling the dice, especially if you’re over 40.

So, How Many People Will Die?

To return to the title of this piece, I don’t know. My guess would be anywhere from 1–100 million. The point isn’t to predict the future but to give you a framework for thinking about it. For a long time, we’ve all been thinking this would just blow over, but I don’t think that’s going to happen. This coronavirus is here, perhaps for many more seasons unless we develop and deploy a vaccine.

The cat is out of the bag and the WHO and scientists are saying to prepare for a pandemic. In this case, it looks like COVID-19 will spread at least as far as the 2009 swine flu, and be much more deadly, especially to the old.

The real question, then, is how deadly is it, and how much control can we get? That’s the 100 million person question. I hope we get it right.

Further Reading

COVID-19 May Infect Half The World
Don’t panic, but this is getting pandemic