25 ms·

Based on Diamond Princess data, where almost everyone was tested, the lower bound of COVID19's IFR (Infection Fatality Rate) should be > 0.5% for many/most coun

Based on Diamond Princess data, where almost everyone was tested, the lower bound of COVID19's IFR (Infection Fatality Rate) should be > 0.5% for many/most countries. This uses a data source independent from what the paper uses. Here's the calculation... Current Diamond Princess' CFR (Case Fatality Rate) is at 11 deaths / 712 infected = ~1.54%. Ten more are in serious/critical conditions, so it could increase. Since testing in DP was almost universal, IFR ~= CFR. DP's demographics is representative of > 30% of population of many/most countries. (See figure 1 here: https://wattsupwiththat.com/2020/03/16/diamond-princess-mysteries/ https://wattsupwiththat.com/2020/03/16/diamond-princess-myst...) Assuming no one in other age groups/health conditions in a country of interest dies (unrealistic) and everyone from Diamond Princess who is in severe/critical condition recovers (optimistic), population's IFR would be = 1.54%/0.3 = ~0.51%. Also, cases from Diamond Princess have received good care. If the healthcare system gets overwhelmed as has happened in many places, population's IFR would shoot up to multiple times as high. Thus, 0.5% is a lower bound for COVID19's IFR, unless a better treatment protocol/medication is invented. Alternatively, if there are successful measures to shield the elderly from getting infected, a region's overall IFR could be lowered.

learc83 7y ago
>DP's demographics is representative of > 30% of population of most countries. However no one under 70 died from what I've read. So we can only get an upper bound on CFR for people under 70.
- nopinsight 7y ago
  For a country with ~10% over 70 years old, and assuming infection fatality rate of ~6% among those, then IFR would already be 0.6%. So suppose that what you've read is the current statistics, it does not contradict the calculation above. People 65 and over comprise >16% of US population, which is relatively young for a developed country. Here's US age structure: https://www.indexmundi.com/united_states/age_structure.html https://www.indexmundi.com/united_states/age_structure.html
  - jonhohle 7y ago
    Not everyone over 70 will be infected. edit: bad math
    - nopinsight 7y ago
      IFR = #fatalities/#infected. You might think of Attack Rate, the % of population who are infected.
      - jonhohle 7y ago
        You’re right, my mistake. Doesn’t this still assume even distribution across all ages? With current testing (at least in the US) people >=70 are more likely to have other conditions which complicate infection and therefore more likely to be tested.
  - quietbritishjim 7y ago
    Everything you've said here is consistent with the parent comment. You've got a lower bound on the infection fatality rate of the whole population, given the usual distribution of ages. But you've only got an upper bound on the fatality rate of a population artificially chosen to have an age distribution that includes nobody over 70. (Actually you do have a lower bound but it's 0%.) That is relevant to anyone who's under 70 and is asking about a population who's only member is themself.
    - nopinsight 7y ago
      Yes and I'm saying there's no contradiction. :) My calculation above simply does not answer the question regarding IFR for each age group. It is based on overall statistics from Diamond Princess. The sample size from DP might be too small to answer the question, esp for younger age groups with lower IFR. We might need to look at data from South Korea and Germany, for example, to estimate those. It would require a more complicated model since testing in any country is not universal.
  - kbutler 7y ago
raverbashing 7y ago
Yeah, two things worry me about Covid: the fact that the percentage is non-negligible even for young people and that the variance between case severities is high, even to the point where people think they don't have it but do.
Retric 7y ago
DP excludes the extreme elderly and sick. Remember, people in nursing care don’t go on cruse ships. Further, it’s expected to see additional deaths. So, such simplistic estimates are completely worthless from their data. What it does do is provide estimates of the rate of infection vs obvious and extreme symptoms. China’s CFR is over 4% and rising, but it’s known that they missed a huge portion of the total case load. PS: Further to estimate for the US population you need further adjustments. China has a younger population than the US with only 10.8% of the population being 65 and older, but they also have more air pollution etc.
- fortran77 7y ago
  Obesity plays a big role in Covid-19 deaths. 33% of Americans are obese, and 65% are overweight. There's a possibility that more obese people take cruises--it fits their lifestyles (unlimited food availability, and they don't have to move much). So the DP data may be tempered by more obesity even though it has less extreme elderly. Also many of the crew got infected. So the amount of viral exposure may play a big part. People who had to come in contact with dozens of infected individuals every day may be the most vulnerable. This doesn't bode well for retail grocery workers.
  - Retric 7y ago
    Of the 712 DP infections, 145 occurred in crew average age 36 and 567 occurred in passengers average age 69. Far from every passenger was obese and few crew where obese. So, I doubt obesity was that far from US norms.
  - staz 7y ago
    > Many obese people take cruises--it fits their lifestyles (unlimited food availability, and they don't have to move much). Do you have actual data on that or is this just your prejudice speaking?
    - jdm2212 7y ago
      Anecdata: I've taken three cruises over the last twenty years, and the obesity rate on those was an order of magnitude higher than what I see in my everyday life as a coastal yuppie -- the only other place I've seen that many people who are that fat was at Disney in Orlando. But America as a whole has a way higher obesity rate than what I see normally, so cruises might just be representative of the country in general.
sct202 7y ago
Using the demographics of just the passengers is misleading because there's basically 1 staff per 2 passengers. Most of the staff are 20-40s.
watoc 7y ago
> 1.54%/0.3 = ~0.51%. Shouldn't this be 11 / (712 / 0.3) which is 1.54 * 0.3 = 0.462
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rhacker 7y ago
Testing may be inaccurate to up to 40% of cases. Not only because the tests are faulty (less likely), but because the virus is not present at the collection spot all the time (more likely) especially if the virus has entered but not yet multiplied enough. It is highly likely based on how this spreads that every single passenger has it right now. Also, these ships may have a much higher death rate due simply because viral load may be much higher (another factor we are still guessing it). If the body gets a strong dose when the infection first happens, the anti-body building process may not be fast enough to fight it off. If the body gets a very small load, it is more likely to start combating the virus, perhaps at a rate slower than replication rate, but eventually it can kill off even a major infection as long as it entered slowly.
- nopinsight 7y ago
  I think they test the passengers there several times over a period of time. Need to check to be sure. Viral load is a key issue but will be applicable to many countries too. See my answer to a sibling comment by hellofunk on this.
hellofunk 7y ago
> Based on Diamond Princess data, where almost everyone was tested, the lower bound of COVID19's IFR (Infection Fatality Rate) should be > 0.5% for many/most countries. No, you can't compare a country's likely outcome to that of a cruise ship. On ships, the virus propogates very differently and the viral load will likely be much higher in infections due to constant contact while onboard. When viral loads are higher, the severity of the disease and mortality rate are also much higher [0]. [0] https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral-dose.html https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral...
- nopinsight 7y ago
  That's a good point. It depends on how many infections on DP occurred after passenger isolations & mitigation measures, which would also lower viral load. I'm not sure we have that data. They stayed on the cruise for a long time. A Japanese expert went on the ship to examine the practice and he was very concerned of further infections. Viral load from infection on DP would be quite close to those living in the same apartment/house/nursing home. In a country with multi-generation households, the viral load could be similar, unless measures are well taken. In other countries, the viral load would depend on how well the elderly are shielded from infection.
loftyal 7y ago
The test they gave only tests for live viral load. It's possible there were cases that were asymptomatic, the immune system took care of it, and when tested they showed no virus, even though they had it. The only real way we can know for sure is giving mass random antibody tests to a population.
winddude 7y ago
CFR needs to use closed case. Either dead or recovered. Currently 21% world wide.
jobigoud 7y ago
> DP's demographics is representative of > 30% of population of many/most countries. Regarding age maybe but what about health? Could there be a higher representation of people that have a long illness and want to go on a cruise before they can't?

learc83 7y ago

>DP's demographics is representative of > 30% of population of most countries. However no one under 70 died from what I've read. So we can only get an upper bound on CFR for people under 70.

nopinsight 7y ago
For a country with ~10% over 70 years old, and assuming infection fatality rate of ~6% among those, then IFR would already be 0.6%. So suppose that what you've read is the current statistics, it does not contradict the calculation above. People 65 and over comprise >16% of US population, which is relatively young for a developed country. Here's US age structure: https://www.indexmundi.com/united_states/age_structure.html https://www.indexmundi.com/united_states/age_structure.html
- jonhohle 7y ago
  Not everyone over 70 will be infected. edit: bad math
  - nopinsight 7y ago
    IFR = #fatalities/#infected. You might think of Attack Rate, the % of population who are infected.
    - jonhohle 7y ago
      You’re right, my mistake. Doesn’t this still assume even distribution across all ages? With current testing (at least in the US) people >=70 are more likely to have other conditions which complicate infection and therefore more likely to be tested.
- quietbritishjim 7y ago
  Everything you've said here is consistent with the parent comment. You've got a lower bound on the infection fatality rate of the whole population, given the usual distribution of ages. But you've only got an upper bound on the fatality rate of a population artificially chosen to have an age distribution that includes nobody over 70. (Actually you do have a lower bound but it's 0%.) That is relevant to anyone who's under 70 and is asking about a population who's only member is themself.
  - nopinsight 7y ago
    Yes and I'm saying there's no contradiction. :) My calculation above simply does not answer the question regarding IFR for each age group. It is based on overall statistics from Diamond Princess. The sample size from DP might be too small to answer the question, esp for younger age groups with lower IFR. We might need to look at data from South Korea and Germany, for example, to estimate those. It would require a more complicated model since testing in any country is not universal.
- kbutler 7y ago

raverbashing 7y ago

Yeah, two things worry me about Covid: the fact that the percentage is non-negligible even for young people and that the variance between case severities is high, even to the point where people think they don't have it but do.

Retric 7y ago

DP excludes the extreme elderly and sick. Remember, people in nursing care don’t go on cruse ships. Further, it’s expected to see additional deaths. So, such simplistic estimates are completely worthless from their data. What it does do is provide estimates of the rate of infection vs obvious and extreme symptoms. China’s CFR is over 4% and rising, but it’s known that they missed a huge portion of the total case load. PS: Further to estimate for the US population you need further adjustments. China has a younger population than the US with only 10.8% of the population being 65 and older, but they also have more air pollution etc.

fortran77 7y ago
Obesity plays a big role in Covid-19 deaths. 33% of Americans are obese, and 65% are overweight. There's a possibility that more obese people take cruises--it fits their lifestyles (unlimited food availability, and they don't have to move much). So the DP data may be tempered by more obesity even though it has less extreme elderly. Also many of the crew got infected. So the amount of viral exposure may play a big part. People who had to come in contact with dozens of infected individuals every day may be the most vulnerable. This doesn't bode well for retail grocery workers.
- Retric 7y ago
  Of the 712 DP infections, 145 occurred in crew average age 36 and 567 occurred in passengers average age 69. Far from every passenger was obese and few crew where obese. So, I doubt obesity was that far from US norms.
- staz 7y ago
  > Many obese people take cruises--it fits their lifestyles (unlimited food availability, and they don't have to move much). Do you have actual data on that or is this just your prejudice speaking?
  - jdm2212 7y ago
    Anecdata: I've taken three cruises over the last twenty years, and the obesity rate on those was an order of magnitude higher than what I see in my everyday life as a coastal yuppie -- the only other place I've seen that many people who are that fat was at Disney in Orlando. But America as a whole has a way higher obesity rate than what I see normally, so cruises might just be representative of the country in general.

sct202 7y ago

Using the demographics of just the passengers is misleading because there's basically 1 staff per 2 passengers. Most of the staff are 20-40s.

watoc 7y ago

> 1.54%/0.3 = ~0.51%. Shouldn't this be 11 / (712 / 0.3) which is 1.54 * 0.3 = 0.462

deleted 7y ago
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deleted 7y ago
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rhacker 7y ago

Testing may be inaccurate to up to 40% of cases. Not only because the tests are faulty (less likely), but because the virus is not present at the collection spot all the time (more likely) especially if the virus has entered but not yet multiplied enough. It is highly likely based on how this spreads that every single passenger has it right now. Also, these ships may have a much higher death rate due simply because viral load may be much higher (another factor we are still guessing it). If the body gets a strong dose when the infection first happens, the anti-body building process may not be fast enough to fight it off. If the body gets a very small load, it is more likely to start combating the virus, perhaps at a rate slower than replication rate, but eventually it can kill off even a major infection as long as it entered slowly.

nopinsight 7y ago
I think they test the passengers there several times over a period of time. Need to check to be sure. Viral load is a key issue but will be applicable to many countries too. See my answer to a sibling comment by hellofunk on this.

hellofunk 7y ago

> Based on Diamond Princess data, where almost everyone was tested, the lower bound of COVID19's IFR (Infection Fatality Rate) should be > 0.5% for many/most countries. No, you can't compare a country's likely outcome to that of a cruise ship. On ships, the virus propogates very differently and the viral load will likely be much higher in infections due to constant contact while onboard. When viral loads are higher, the severity of the disease and mortality rate are also much higher [0]. [0] https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral-dose.html https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral...

nopinsight 7y ago
That's a good point. It depends on how many infections on DP occurred after passenger isolations & mitigation measures, which would also lower viral load. I'm not sure we have that data. They stayed on the cruise for a long time. A Japanese expert went on the ship to examine the practice and he was very concerned of further infections. Viral load from infection on DP would be quite close to those living in the same apartment/house/nursing home. In a country with multi-generation households, the viral load could be similar, unless measures are well taken. In other countries, the viral load would depend on how well the elderly are shielded from infection.

loftyal 7y ago

The test they gave only tests for live viral load. It's possible there were cases that were asymptomatic, the immune system took care of it, and when tested they showed no virus, even though they had it. The only real way we can know for sure is giving mass random antibody tests to a population.

winddude 7y ago

CFR needs to use closed case. Either dead or recovered. Currently 21% world wide.

jobigoud 7y ago

> DP's demographics is representative of > 30% of population of many/most countries. Regarding age maybe but what about health? Could there be a higher representation of people that have a long illness and want to go on a cruise before they can't?