Covid19 Vs Flu: Is Covid19 Deadlier?

Is it a deadly pandemic or just another flu?

You may have noticed certain public figures or close friends of yours question how deadly the Covid19 virus is. You may have even done it yourself. I know I have wondered in the back of my mind if it is really as bad as it seems. This doubt, combined with news fatigue has left even the most critical thinking amongst us to wonder, is Covid19 really that bad?

Let’s take a rational look at this, with no political bias (at least as little as possible) and good solid data to answer the question, is Covid19 deadlier than the flu?

Firstly, let’s look at the mortality rate of both viruses (what percentage of people who catch the virus die from it). This has not been easy to estimate for Covid19, as not everyone with Covid19 has been tested, so we don’t actually know how many people have it!

This is why at the beginning of the pandemic, WHO (World Health Organisation) estimated the mortality rate of Covid19 to be 3%–4%. They could only estimate how many people had it and did not want to underestimate the virus. In short, they were taking the worst-case scenario and preparing people for it.

Our estimates for the mortality rate still aren’t 100% accurate. There aren’t enough Covid19 testing kits to test a whole country in one go, so we will never know how many people truley have it.

But, there is one place where we can be sure of the number of people who caught it and that have died from it, cruise ships—namely the Diamond Princess, where the virus took ahold. Of the 3711 passengers and crew, 705 caught the virus, of which 7 died.

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Diamond Princess in 2016 — WikiCC

This means that 0.99% of those who caught the virus died, which is close to the adjusted estimates from countrywide infections and deaths. This means that, while this isn’t a 100% accurate figure, it must be damn close.

This means that Covid19 is less deadly than it’s predecessors SARS and MERS. But this shouldn’t be surprising. To cause a widespread pandemic a virus can’t be too deadly, otherwise, it can’t spread through the population effectively. This is one of the reasons why Covid19 has had such a huge impact.

How does this mortality rate compare to the common flu, also known as influenza?

Firslty, it is important to note that their isn’t just one influenza, It technically refers to a group of virus, as does Coronavirus (we are talking about Coronavirus I.D 19, or Covid19). The influenza I am referring to here is the common cold, also known as the flu, which has a consistent mortality rate and infection rate despite year on year mutations.

Flu has a much lower mortality rate at 0.01%, making Covid19 ten times more deadly. While we have had some dramatic advances in treating Covid19 patients, there has been nothing which can reduce the death rate by tenfold.

This mortality rate for the flu and Covid19 is calculated across all race, gender, health and age. But we know that some groups are more susceptible to die from either virus. Does that mean that if you are in your 20s or 30s that your mortality rate is significantly lower than the elderly for Covid19, just like the flu?

Whilst it is very rare for someone to die of influenza at a young age, with no health issue, it is surprisingly common in Covid19. So the influenza mortality rate is dramatically different for people in their 20s compared to people in their 80s. In fact, most countries have a 0% mortality rate of influenza in under 30s.

But Covid19 is not quite as skewed as influenza. It is still the case that the mortality rate gets higher for older people, but Covid19 regularly kills people younger than 40 or 30. In fact, for 30–39 year-olds, the death rate from Covid19 is about the same as influenza’s overall rate at 0.01%. In comparison, 80–89 year-olds have a Covid19 mortality rate of 13.4%.

For the 30-year-olds reading this, 0.01% might sound like a tiny chance. It is one in a thousand after all. But this is the same as your chances of contracting HIV or dying in a house fire and is more likely than you drowning. So, it isn’t so small that you shouldn't worry about it, it is a genuine threat that you should take seriously.

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Photo by Daniel Tausis on Unsplash

So, for those who catch Covid19, their chances of dying are about ten times higher than of the flu, at the very least. But what if ten times less people are catching it compared to influenza?

This was a question I asked myself repeatedly. I only know one person who has tested positive for Covid19 and during flu season loads of people around me get it. Does that mean Covid19 is less infectious? Well, my personal experience isn’t a large enough sample group, so we can discount it.

Covid19 is more infectious than the flu; the only reason I don’t know loads of people with it is because we have been in lockdown and with social distancing measures. So it hasn’t spread as much as flu does at its peak, at least where I live.

Why is Covid19 more infectious?

Covid19 has a longer incubation period than influenza (you are infected but don’t show any symptoms). Influenza has an incubation period of one day but Covid19 can have an incubation period of up to 14 days. The flu also becomes less infectious quicker. With influenza you are infectious during the incubation period, but you stop spreading the virus after a week. Covid19 is also infectious during its’ incubation period, and we don’t know when you stop being contagious from it, you could be contagious for up to a month.

This is why influenza spreads slowly; you can only really pass it to the people you can meet in one day and then the people in your home as you recover. But some individuals with Covid19 can be up and about for two weeks before realising they have it. This means you get pockets of outbreaks caused by a single ‘superspreader’, who didn’t realise they were infected, spreading it to thousands.

This is why simulations show that up to 80% of a population could catch Covid19 if no measures were put in place. Meanwhile, similar outbreaks of influenza only infect up to 11% of a population.

So, Covid19 is more deadly and more infectious than the flu. But how much worse is it?

Well, we have the percentage of the population that would catch Covid19 (if no measures were in place) and influenza and the death rates for both. Let’s pick a country a see how many people would die from Covid19 and Influenza to get a scale of how much more deadly Covid19 is. As most of my readers are US based, let’s do it there.

The USA currently has a population of 328.2 million. Over the course of an outbreak influenza would infect around 36.1 million people, Covid19 would infect 262.56 million. Influenza would kill 36,100 people, and Covid19 would kill 2.63 million.

That is 72.9 times more Covid19 deaths than influenza deaths! Another way of looking at it is that Covid19 could kill the equivalent to the population of Houston, Texas if it went unchecked in the USA.

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Centeral Houston, Texas — WikiCC

These aren’t 100% accurate figures, and shouldn’t be taken as absolutes, but they are close to accurate. Influenza killed 34,200 Americans last year which is damn close to our estimates here. These numbers show just how deadly the Covid19 virus is.

So, how deadly is Covid19?

Well, our calculations show that it is 7290% more deadly than influenza. However, if you don’t trust me, then trust the consensus of the leading global scientists and medical experts, which is, this virus is more viral and deadly than anything we have come across in our life time. After all, if 99 doctors tell you smoking is bad and 1 tells you that it’s fine, you would believe the 99.

So, if you hear a public figure or a friend say that Covid19 is just another flu, you can tell them that it is a lot more deadly and show them evidence to back you up.

Science writer of space, environment, and technology. I show you the wonders and terrors of our universe & its future. Follow me at

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