> the real fatality rate could in fact be closer to 0.06%
If you take a look at Diamond Princess.
~ 4000 on board
* 712 cases
* 10 deaths
Gives a case fatality rate of 1.4%.
The average age onboard was ~60 years (don't know if it includes staff) which is definitely higher than average.
However, the two numbers (1.4% and 0.06%) sounds very far apart.
Another factor is viral load. More evidence is coming out that the total exposure can be a big factor in severity of symptoms and risk of death. This is likely partly why healthcare workers, including young ones, are often becoming grievously ill and sometimes dying.
In a confined space that everyone is stuck in for an extended period of time, people are continuously getting exposed and re-exposed to the virus, and those people are getting infected and continuously re-exposing everyone else. The ship eventually becomes a frothing virus stew.
Maybe one exposure ends up with a bit in your mouth from a nearby cough, and then another from your hand touching a surface and then wiping your nose or eyes with the back of your hand, etc., and then those keep happening over and over. Without proper ventilation, everyone will be getting exposed from breathing the same air in certain rooms, too. The frequent exposures give it more numbers that need to be fended off and more footholds to gain in different internal areas.
Then combine that with the high average age, lack of adequate medical care on the ship, general ignorance over the virus at that point, maybe re-use of unwashed clothes or hats.
Extrapolating from an environment like a ship or a hospital should be done carefully.
That's kind of right. The shear number of viruses that begin the infection, and also possibly over the first week or so, affect how hard it hits you. After the first week, your body is producing huge amounts of antibodies against the virus and it's not likely a factor anymore. Someone posted a link in another thread about a commercially available antibody test kit. The product page showed a nice graph of the timing of the antibody response (IgM shows up after the first week and IgG later). Now I can't find it. Anyone have that link?
Thanks, this makes sense. I imagine cruise passengers and hospital workers are pretty likely to get a lot of initial exposure in a short period of time, but people who get occasionally re-exposed through day-to-day life are probably at much less risk.
Except that the US isn't composed of 327 million 39 year olds, it's composed of a fairly even mix of people of various ages. If you multiply the case fatality rates from your link [1] by the population in each age bracket [2], you come up with a projected CFR of about 1.8% in the US, assuming that a similar fraction of people in each age range are infected.
It is impossible to calculate this from just the medians. John Ioannidis estimates a range of 0.025% to 0.625% by comparing the age distributions. However, there is so little data that any small systematic error could completely invalidate this.
Now imagine a population that was averaged in the 30's years. What do you imagine the death rate to be then? it wouldn't be half, as it scales non linearly the younger the person gets.
As you say, the average age is high, which makes a big difference, but some people think there were more cases than the confirmed ones on the boat. That could explain the difference.
If you take a look at Diamond Princess.
~ 4000 on board
* 712 cases
* 10 deaths
Gives a case fatality rate of 1.4%.
The average age onboard was ~60 years (don't know if it includes staff) which is definitely higher than average. However, the two numbers (1.4% and 0.06%) sounds very far apart.