5 ms·

Side question: The very first comparison of covid-19 and seasonal flu I read (before covid-19 was called covid-19) said that covid-19 would have a mortality ra

by nednar 6y ago

Side question: The very first comparison of covid-19 and seasonal flu I read (before covid-19 was called covid-19) said that covid-19 would have a mortality rate of 1.5% and seasonal flu of 3%, therefore covid-19 would be less deadly. In recent months I often read the same statement turned around, which is already confusing. Now here we talk about a tenth of the same numbers turned around. I mean, either it's not standardized what "mortality rate" means or the numbers are all over the place and one can't really say which is more deadly. Could someone with more knowledge in this area summarize the current status and maybe where the confusions might come from?

salty_biscuits 6y ago
Maybe loose terminology so ending up getting case fatality rate confused with mortality rate?
Gwypaas 6y ago
It's the difference between IFR and CFR. The IFR is the infection fatality rate meaning everyone in the population who has been infected. The CFR is the case fatality rate, those who are sick enough to show up at a hospital, or well, get tested and confirmed positive. Which nowadays is essentially the same and a small fraction of total cases. We see here that flu seems to have an overall IFR rate of 0.002%. Many orders of magnitude smaller than COVID19. https://www.cdc.gov/nchs/fastats/flu.htm https://www.cdc.gov/nchs/fastats/flu.htm
- aquadrop 6y ago
  Where do you get IFR for covid19?
  - Gwypaas 6y ago
    The IFR rate for covid-19 seems to be trending towards 0.1-0.5% based on the serological tests over entire population cohorts that are starting to be published.
    - rocha 6y ago
      I thought it was between 0.5% to 1.0%, at least according to the NYC study: https://twitter.com/trvrb/status/1253436656742305793 https://twitter.com/trvrb/status/1253436656742305793
  - vianneychevalie 6y ago
    By doing serologic studies you can estimate the global number of contaminated people: looking at the number of viral mutations, as well as different strands of the virus that can be identified as being generated in a specific region. It’s going to be very imprecise. For H1N1 the global infection rate could have varied from 11% to 21% of the global population, which is a +/- 350 million people estimation. https://www.cidrap.umn.edu/news-perspective/2011/08/study-puts-global-2009-h1n1-infection-rate-11-21 https://www.cidrap.umn.edu/news-perspective/2011/08/study-pu...
- nednar 6y ago
  0.002% is again a different number than 3%, 1.5%, 0.3% and 0.15%. Also to compare two numbers don't you need a second one as well? 0.00002 is a magnitute smaller than what number?
  - Gwypaas 6y ago
    The IFR rate for covid-19 seems to be trending towards 0.1-0.5% based on the serological tests over entire population cohorts that are starting to be published.
- votepaunchy 6y ago
  According to the CDC, the seasonal flu kills 12,000-79,000 Americans a year by the same standard as used for COVID-19. Much closer to the widely cited 0.1% IFR. https://www.cdc.gov/flu/about/burden/faq.htm https://www.cdc.gov/flu/about/burden/faq.htm
  - Gwypaas 6y ago
    Seems high. Here is a systemic review of studies done on the 2009 influenza coming to a conclusion of an IFR of 1-10 deaths per 100 000 infections. "The consistent estimates of the infection fatality risk at around 1 to 10 deaths per 100,000 infections identified in our review" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809029/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809029/
    - arcticbull 6y ago
      CEBM concurs, the H1N1 CFR was between 0.1% and 5.1%, based on country and the fatality risk settled out at 0.02%. [1] Some more napkin math, the CDC estimates between 12,000 and 61,000 flu fatalities per year out of approximately 9,300,000 to 45,000,000 infections so pretty consistently a 0.1-0.15% IFR. [2] Not sure how to reconcile these. The worst year, 2017-2018, had 45M cases and 61K deaths. The dominant strain was H3N2 not H1N1. The vaccine wasn't particularly effective that year (38%). Not sure how else to account for the delta. [3, 4] [1] https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/ https://www.cebm.net/covid-19/global-covid-19-case-fatality-... [2] https://www.cdc.gov/flu/about/burden/index.html https://www.cdc.gov/flu/about/burden/index.html [3] https://www.cdc.gov/flu/about/burden/2017-2018.htm https://www.cdc.gov/flu/about/burden/2017-2018.htm [4] https://www.cdc.gov/flu/vaccines-work/effectiveness-studies.htm https://www.cdc.gov/flu/vaccines-work/effectiveness-studies....
- spikels 6y ago
  > Deaths per 100,000 population: 2.0 Your 0.002% number is the POPULATION Fatality Rate not the Infection Fatality Rate (IFR).
abdullahkhalids 6y ago
Remember that IFR of a disease alone does not tell you how many people ultimately die from it. The R0 number, which determines how quickly the diseases spread, determines total cases and then cases X IFR = deaths. My understanding is that Covid-19 has a much higher R0 than the seasonal flu.
9wzYQbTYsAIc 6y ago
One thing that didn’t seem to be noted in the rest of the comments: the actual mortality rate can’t be formally calculated until the pandemic has subsided. What you are seeing now are estimates and projections for the number that they’ll end up being able to calculate when the disease has stopped spreading.
JamesBarney 6y ago
If someone said the flu has a 3% ifr (infection fatality rate) they were way off. The best guess for the covid-19 IFR I've seen is ~1%. New York City has has .02% of it population die above the base death(excess deaths). And the last serological study said 20% of people have been infected. So that gives us an approximation of 1%. This is 10x-100x worse than the flu.
- jsjohnst 6y ago
  > New York City has has .02% of it population die above the base death(excess deaths) Where did you get that number? The numbers I’ve seen are several orders of magnitude higher.
  - speakeron 6y ago
    2% (2 orders of magnitude above 0.02%) of 8 million (approximately the population of NYC) is 160,000 people. So that's clearly wrong being more than 3 times the entire US deaths. The numbers you've seen are probably deaths of infected people not the entire population.
    - deleted 6y ago
      [deleted]
    - jsjohnst 6y ago
      > The numbers you've seen are probably deaths of infected people not the entire population. No, I just slightly misread OP’s confusingly worded stat. Base deaths in NYC is around 6k/month. Covid-19 deaths alone have been way above that number. Numbers are obviously not in for the month of April yet, but it’s looking more like it’ll be closer to 30k deaths in NYC per CDC[0]. So that’s 24k more deaths per month, aka 5x (where my several orders of magnitude came from). If you use the scale OP used, that’s about .3% of NYC population in excess deaths, so one order of magnitude higher. [0] it’s at 26k right now with a bit under a week left - https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm
  - JamesBarney 6y ago

by nednar 6y ago

salty_biscuits 6y ago

Maybe loose terminology so ending up getting case fatality rate confused with mortality rate?

Gwypaas 6y ago

It's the difference between IFR and CFR. The IFR is the infection fatality rate meaning everyone in the population who has been infected. The CFR is the case fatality rate, those who are sick enough to show up at a hospital, or well, get tested and confirmed positive. Which nowadays is essentially the same and a small fraction of total cases. We see here that flu seems to have an overall IFR rate of 0.002%. Many orders of magnitude smaller than COVID19. https://www.cdc.gov/nchs/fastats/flu.htm https://www.cdc.gov/nchs/fastats/flu.htm

aquadrop 6y ago
Where do you get IFR for covid19?
- Gwypaas 6y ago
  The IFR rate for covid-19 seems to be trending towards 0.1-0.5% based on the serological tests over entire population cohorts that are starting to be published.
  - rocha 6y ago
    I thought it was between 0.5% to 1.0%, at least according to the NYC study: https://twitter.com/trvrb/status/1253436656742305793 https://twitter.com/trvrb/status/1253436656742305793
- vianneychevalie 6y ago
  By doing serologic studies you can estimate the global number of contaminated people: looking at the number of viral mutations, as well as different strands of the virus that can be identified as being generated in a specific region. It’s going to be very imprecise. For H1N1 the global infection rate could have varied from 11% to 21% of the global population, which is a +/- 350 million people estimation. https://www.cidrap.umn.edu/news-perspective/2011/08/study-puts-global-2009-h1n1-infection-rate-11-21 https://www.cidrap.umn.edu/news-perspective/2011/08/study-pu...
nednar 6y ago
0.002% is again a different number than 3%, 1.5%, 0.3% and 0.15%. Also to compare two numbers don't you need a second one as well? 0.00002 is a magnitute smaller than what number?
- Gwypaas 6y ago
  The IFR rate for covid-19 seems to be trending towards 0.1-0.5% based on the serological tests over entire population cohorts that are starting to be published.
votepaunchy 6y ago
According to the CDC, the seasonal flu kills 12,000-79,000 Americans a year by the same standard as used for COVID-19. Much closer to the widely cited 0.1% IFR. https://www.cdc.gov/flu/about/burden/faq.htm https://www.cdc.gov/flu/about/burden/faq.htm
- Gwypaas 6y ago
  Seems high. Here is a systemic review of studies done on the 2009 influenza coming to a conclusion of an IFR of 1-10 deaths per 100 000 infections. "The consistent estimates of the infection fatality risk at around 1 to 10 deaths per 100,000 infections identified in our review" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809029/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809029/
  - arcticbull 6y ago
    CEBM concurs, the H1N1 CFR was between 0.1% and 5.1%, based on country and the fatality risk settled out at 0.02%. [1] Some more napkin math, the CDC estimates between 12,000 and 61,000 flu fatalities per year out of approximately 9,300,000 to 45,000,000 infections so pretty consistently a 0.1-0.15% IFR. [2] Not sure how to reconcile these. The worst year, 2017-2018, had 45M cases and 61K deaths. The dominant strain was H3N2 not H1N1. The vaccine wasn't particularly effective that year (38%). Not sure how else to account for the delta. [3, 4] [1] https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/ https://www.cebm.net/covid-19/global-covid-19-case-fatality-... [2] https://www.cdc.gov/flu/about/burden/index.html https://www.cdc.gov/flu/about/burden/index.html [3] https://www.cdc.gov/flu/about/burden/2017-2018.htm https://www.cdc.gov/flu/about/burden/2017-2018.htm [4] https://www.cdc.gov/flu/vaccines-work/effectiveness-studies.htm https://www.cdc.gov/flu/vaccines-work/effectiveness-studies....
spikels 6y ago
> Deaths per 100,000 population: 2.0 Your 0.002% number is the POPULATION Fatality Rate not the Infection Fatality Rate (IFR).

abdullahkhalids 6y ago

Remember that IFR of a disease alone does not tell you how many people ultimately die from it. The R0 number, which determines how quickly the diseases spread, determines total cases and then cases X IFR = deaths. My understanding is that Covid-19 has a much higher R0 than the seasonal flu.

9wzYQbTYsAIc 6y ago

One thing that didn’t seem to be noted in the rest of the comments: the actual mortality rate can’t be formally calculated until the pandemic has subsided. What you are seeing now are estimates and projections for the number that they’ll end up being able to calculate when the disease has stopped spreading.

JamesBarney 6y ago

If someone said the flu has a 3% ifr (infection fatality rate) they were way off. The best guess for the covid-19 IFR I've seen is ~1%. New York City has has .02% of it population die above the base death(excess deaths). And the last serological study said 20% of people have been infected. So that gives us an approximation of 1%. This is 10x-100x worse than the flu.

jsjohnst 6y ago
> New York City has has .02% of it population die above the base death(excess deaths) Where did you get that number? The numbers I’ve seen are several orders of magnitude higher.
- speakeron 6y ago
  2% (2 orders of magnitude above 0.02%) of 8 million (approximately the population of NYC) is 160,000 people. So that's clearly wrong being more than 3 times the entire US deaths. The numbers you've seen are probably deaths of infected people not the entire population.
  - deleted 6y ago
    [deleted]
  - jsjohnst 6y ago
    > The numbers you've seen are probably deaths of infected people not the entire population. No, I just slightly misread OP’s confusingly worded stat. Base deaths in NYC is around 6k/month. Covid-19 deaths alone have been way above that number. Numbers are obviously not in for the month of April yet, but it’s looking more like it’ll be closer to 30k deaths in NYC per CDC[0]. So that’s 24k more deaths per month, aka 5x (where my several orders of magnitude came from). If you use the scale OP used, that’s about .3% of NYC population in excess deaths, so one order of magnitude higher. [0] it’s at 26k right now with a bit under a week left - https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm
- JamesBarney 6y ago