EDIT: After reading the comments and learning more about the current outbreak, I see that the premise of my question is incorrect. I mistakenly believed that the virus' mortality rate was around the same as that of the flu, when in fact it's much higher.

My understanding is that the virus' mortality rate is around 2%, which is similar to the flu. It's less deadly than SARS.

So why are people so worried, and why are governments going to such extreme measures to prevent it from spreading? My guesses are:

  • We don't know enough about the long-term effects of the virus, so better safe than sorry
  • The economic and social disruption caused by robust measures (e.g., quarantining) costs less than letting a new disease become pandemic, even if it isn't particularly deadly
  • Mass hysteria fueled by the media and misinformation
  • Governments feeling like they have to appear responsive to popular concern lest they seem lazy
  • This virus affects more developed parts of the world, so it's more visible
  • The Chinese government's over-the-top, authoritarian, "only in China"-style measures have left everyone in such awe that they think, "this must be really serious!" (When in fact the government's real intention is perhaps to cover up how badly they botched their initial handling of the outbreak.)

As for one's chances of coming into contact with the virus, the total number of confirmed cases in the world as of writing is around 80k. Let's say that the true number is double that, or 160,000. That's still only ~1.5% of the population of Wuhan, the city where the initial outbreak occurred. Why should anyone be in the slightest bit concerned about going for a stroll down the main street?

I'm not an expert in public health or medicine. It would be great to hear an expert's take on this question!

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    This seems like a discussion you want to ave. Discussions are better suited to forums than on Q&A sites such as SE. Feb 26, 2020 at 6:51
  • I'm not looking for a discussion, I'm seeking expert opinions from people working in public health and medicine. I gave my own unlearned opinions as context to so that more knowledgeable people can better address my confusion. Feb 26, 2020 at 16:49
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    A 2% mortality rate is comparable to that from the 1918 flu pandemic. In a normal flu season, the mortality rate is one to three orders of magnitude lower.
    – Mark
    Feb 28, 2020 at 21:13
  • From the CDC site ( for US): there are 9 to 45 million cases of flu causing 12,000 to 61,000 deaths in US each year. Mar 2, 2020 at 20:38

2 Answers 2


The danger posed to society from this disease doesn't come from the mortality rate, rather from the potential to make large fraction of the population ill. Unlike the flu virus, this virus is a new virus to which we have no immunity.

About 10% of the infected people requires hospital treatment, which is a lot higher than in case of flu. The death rate of the order of 1% is achieved thanks to excellent hospital treatment. With a far larger fraction of the population infected with this virus compared to the flu and a far larger fraction of the infected people requiring hospital treatment compared to flu, the available hospital capacity to give everyone the treatment they need can be easily exhausted. The death rate due to the virus will then increase.

Also, people who need treatment for other reasons can then also fail to get prompt medical attention. People suffering a heart attack who would have survived under normal circumstances thanks to getting prompt medical attention, may now end up dying too.

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    Can you please provide citations for your claims? Mar 2, 2020 at 9:43
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    "this virus is a new virus to which we have no immunity" -- Says who? Coronavirus is hardly a new virus. It's responsible for about 10-12% of all common colds so it's quite possible there's some degree of cross-immunity between strains in some people.
    – Carey Gregory
    Mar 3, 2020 at 6:16

If we compare Covid19 to SARS or MERS - COVID19 seems to have a R0 slightly higher than SARS but lower than MERS. From various sources it appears that COVID-19 could be between 2 and 7, so compariable to diseases such as mumps and diphtheria in spread. Infection fatality rates vary wildly right now as the sample size is very small, but from 0.2% up to 18% (18% for early stage Hubei province infections).

Comparisons to other diseases:-Wiki-herd immunity - I wanted to paste the table in here, but SE doesn't seem to support the MD table format


But IMO the primary difference is that SARS and MERS occured before large-scale social-media monetization.. So there was little to gain by media/social media doing a major panic..

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    Welcome to MedicalSciences.SE. We work differently to most SE sites, where we have a strict policy that all answers should be backed up with reliable references so that the answer can be independently verified, regardless of the reader's background. See this list of reliable sources. If you still have trouble with this, feel free to visit the help center or Medical Sciences Meta. Unreferenced claims can lead to answers being deleted. Mar 2, 2020 at 9:45
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    Where are you getting those comparison R0s from? MERS has a much lower R0 in most sources I am aware of.
    – Bryan Krause
    Mar 2, 2020 at 14:32
  • @BryanKrause got a range of 0.45 to 8.1 from wwwnc.cdc.gov/eid/article/26/2/19-0697_article also useful is currents.plos.org/outbreaks/index.html%3Fp=40801.html
    – baradhili
    Mar 3, 2020 at 10:35
  • If the range is 0.45 to 8.1, and especially because the typical range for MERS is <1.0, outside of a couple particular outbreaks, it doesn't seem to make sense to call "2 to 7" less than "0.45 to 8.1".
    – Bryan Krause
    Mar 3, 2020 at 16:27
  • True Bryan, but since the question was around the hyperbole around infections - I figured I should take the maximum reported values..
    – baradhili
    Mar 4, 2020 at 3:38

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