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Comment by tptacek | Hacker News Reader

Just according to superficial stats, it looks like the flu kills orders of magnitude more people than SARS and MERS. Is the public health response to these diseases really so effective as to account for most of this difference? I don't pay close attention but also wouldn't off the top of my head be able to describe anything that, say, Washington State does to effectively respond to CoV incidents to keep it from propagating rapidly through the population the way the flu does.

(I'm asking because I'm curious and seriously have no clue how this stuff works).

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Yes, seasonal flu in the US alone kills around 30,000 each year, and may have killed as many as 60,000 during the 17-18 flu season alone [1]. MERS and SARS have each killed less than 1,000 worldwide.

A few things that may interest you:

* The rate of transmission for a disease is estimated by its R0 or basic reproduction number. R0 estimates the number of new cases from the unaffected population that one infection will cause. A disease with R0 <1 will die out by itself. SARS has an estimated R0 of 3-5, while seasonal flus are between 1 and 2 [2]. So by this measure alone SARS is more "infectious" than the flu. Note that R0 is not a rate and is estimated from mathematical models [3].

* Seasonal flu predominantly kills the young, the elderly, and the immunocompromised. Interestingly, some strains, such as the Spanish Flu, have very different mortality curves that kill healthy middle aged adults far more than average [4]. I would expect a dramatically different public health response compared to normal seasonal flu if a future pandemic had a similar mortality curve.

* In the US, the "tip of the spear" for disease response would be the CDC's Division of Global Migration and Quarantine [5].

[1] https://www.cdc.gov/flu/about/burden/index.html [2] https://www.ncbi.nlm.nih.gov/pubmed/19545404 [3] https://web.stanford.edu/~jhj1/teachingdocs/Jones-on-R0.pdf [4] https://en.wikipedia.org/wiki/Spanish_flu#/media/File:W_curv... [5] https://www.cdc.gov/ncezid/dgmq/quarantine-fact-sheet.html

Just according to superficial stats, it looks like the flu kills orders of magnitude more people than SARS and MERS.

This is the "ratio vs. number" distinction: the seasonal flu, despite seeming to have a mortality rate on the order of 1/1000, killed more people just in the US than estimates of people who contracted SARS at all anywhere in the world.

Flu stats: https://www.cdc.gov/flu/about/burden/index.html

SARS stats: https://www.who.int/csr/sars/country/table2004_04_21/en/

When H1N1 was spreading while I was in college, any people who were confirmed cases would have to undergo two weeks of house quarantine. That's a lot of people saved from potential contact. I imagine Washington State's procedures for quarantine aren't too different.

So lots of people get the flu, but few people die from it.

Few people get SARS/MERS, but they're much more likely to die.

There are a lot of reasons for that. And yes, Washington State can effectively respond to CoV incidents - contact tracing, which is what you need to get people into isolation, is very labor intensive, and probably going on right now. State health departments help support hospitals in doing infection control work (to prevent within hospital transmission) and a lot of coordinating.

> Is the public health response to these diseases really so effective as to account for most of this difference?

Yes. The public health response to the common flu is 'You should, like, get vaccinated. Or whatever. Maybe take a day off, if you work a job that gives you sick days.'

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