Much has been said about the CFR for COVID-19. However, what is clear so far is that it varies greatly from country to country. Mainly because the pathophysiology of this disease depends on many factors.
In any case, assuming that the data so far are complete and have the world average CFR for COVID-19, would it be valid or correct to say (in epidemiological terms) that it is a high CFR disease?
From what value can a disease be said to have a high CFR?
It is an underestimate due to under testing and possibility of very high number of asymptomatic persons contracting COVID-19.
Case fatality rate is actually a crude mortality rate. Definite mortality rate would be known by number of deaths due to COVID-19 and number of people affected at the end of pandemic.
For example, in one Italian town, 60% had asymptomatic COVID-19 infection.
https://www.theguardian.com/commentisfree/2020/mar/20/eradicated-coronavirus-mass-testing-covid-19-italy-vo
The real extent of mortality will be known by antibody testing for SARS-CoV-19 giving an idea of actual exposure rate.
The exact fatality rate is currently unknown because large proportions of infected people go untested or even unsuspected.
https://www.economist.com/graphic-detail/2020/04/11/why-a-study-showing-that-covid-19-is-everywhere-is-good-news
In my opinion, case fatality varies depending on the testing strategies of each country. In this COVID-19, many cases are asymptomatic and they get tested only because on of the family member visits the hospital and found positive for COVID-19. Case fatality rate is a crude mortality rate.
The current estimates of numbers of COVID-19 cases and deaths are very meaningless. The sensitivity and specificity of the diagnostic tests for COVID-19 are not yet known in vivo. There are reports of very high sensitivity and specificity in vitro. However a number of confounding factors (e.g. the stage of illness and the way the swab was taken) mean that the false negative rate of these tests may be high in clinical practice.
Wenling Wang; Yanli Xu; Ruqin Gao; et al Detection of SARS-CoV-2 in Different Types of Clinical Specimens. Jama 2020 (in press).
The numbers of cases reported will also depend on strategies used for screening. Many countries are only screening symptomatic patients presenting to healthcare facilities. Others are attempting to screen a significant proportion of the population.
I believe the total number of cases of COVID-19 is significantly higher than that being reported. There are many confounding factors (both political and diagnostic) that make the initial number of deaths reported as being due to COVID-19 extremely difficult to interpret.
The availability of healthcare in general and specifically critical care will affect case fatality. In China and Italy where large numbers of healthcare professionals were infected the capacity to deliver healthcare was substantially reduced.
Another important factor to consider when trying to interpret variation in mortality rates between countries is differences in cultural interpretation of quality of life. This impacts the social and medical ethics and the delivery, limitation and withdrawal of life sustaining therapies.
In many Western cultures quality of life is valued far more than quantity of life. In those settings limitation and even withdrawal of life sustaining therapies resulting in cardiac arrest are a common mode of death.
In many Eastern cultures quantity of life is valued more than quality of life. In these settings treatment limitations and withdrawals of therapy are rare. Admission to intensive therapy units and prolonged organ support are common. Mode of death is often failure of resuscitation after cardiac arrest.
These differences are magnified when there are limited resources particularly in Western countries. The social and medical acceptance of treatment limitations is increased; this may significantly increase case fatality rates.
Thanks Muhammad Yousuf , David C. Rotzinger , Malangori Parande , and Rajkumar Rajendram for your points of view. However, assuming that the pandemic is over, and that the data is complete (i.e., number of infected and dead), would you think that COVID-19 had a high or low crude mortality rate?
This was forwarded to me via social media. I would love to credit the author but I do not know who it is. It encapsulates the current understanding of Covid-19 so well that I thought everyone would enjoy reading it…
For those of you who are still confused, these are the rules for covid 19:
1. Basically, you can't leave the house for any reason, but if you have to, then you can.
2. Masks are useless, but maybe you have to wear one, it can save you, it is useless, but maybe it is mandatory as well.
3. Stores are closed, except those that are open.
4. You should not go to hospitals unless you have to go there. Same applies to doctors, you should only go there in case of emergency, provided you are not too sick.
5. This virus is deadly but still not too scary, except that sometimes it actually leads to a global disaster.
6. Gloves won't help, but they can still help.
7. Everyone needs to stay HOME, but it's important to GO OUT.
8. There is no shortage of groceries in the supermarket, but there are many things missing when you go there in the evening, but not in the morning. Sometimes.
9. The virus has no effect on children except those it affects.
10. Animals are not affected, but there is still a cat that tested positive in Belgium in February when no one had been tested, plus a few tigers here and there…
11. You will have many symptoms when you are sick, but you can also get sick without symptoms, have symptoms without being sick, or be contagious without having symptoms. Oh, my God.
12. In order not to get sick, you have to eat well and exercise, but eat whatever you have on hand because it's better not to go out, well, but no…
13. It's better to get some fresh air, but you get looked at very wrong when you get some fresh air, and most importantly, you don't go to parks or walk. But don’t sit down, except that you can do that now if you are old, but not for too long or if you are pregnant (but not too old).
14. You can't go to retirement homes, but you have to take care of the elderly and bring them food and medication.
15. If you are sick, you can't go out, but you can go to the pharmacy.
16. You can get restaurant food delivered to the house, which may have been prepared by people who didn't wear masks or gloves. But you have to have your groceries decontaminated outside for 3 hours. Pizza too?
17. Every disturbing article or disturbing interview starts with " I don't want to trigger panic, but…"
18. You can't see your older mother or grandmother, but you can take a taxi and meet an older taxi driver.
19. You can walk around with a friend but not with your family if they don't live under the same roof.
20. You are safe if you maintain the appropriate social distance, but you can’t go out with friends or strangers at the safe social distance.
21. The virus remains active on different surfaces for two hours, no, four, no, six, no, we didn't say hours, maybe days? But it takes a damp environment. Oh no, not necessarily.
22. The virus stays in the air - well no, or yes, maybe, especially in a closed room, in one hour a sick person can infect ten, so if it falls, all our children were already infected at school before it was closed. But remember, if you stay at the recommended social distance, however in certain circumstances you should maintain a greater distance, which, studies show, the virus can travel further, maybe.
23. We count the number of deaths but we don't know how many people are infected as we have only tested so far those who were "almost dead" to find out if that's what they will die of…
24. We have no treatment, except that there may be one that apparently is not dangerous unless you take too much (which is the case with all medications). Orange man bad.
25. We should stay locked up until the virus disappears, but it will only disappear if we achieve collective immunity, so when it circulates… but wait...we must no longer be locked up for that?
This was forwarded to me via social media. I would love to credit the author but I do not know who it is. It encapsulates the current understanding of Covid-19 so well that I thought everyone would enjoy reading it…
For those of you who are still confused, these are the rules for covid 19:
1. Basically, you can't leave the house for any reason, but if you have to, then you can.
2. Masks are useless, but maybe you have to wear one, it can save you, it is useless, but maybe it is mandatory as well.
3. Stores are closed, except those that are open.
4. You should not go to hospitals unless you have to go there. Same applies to doctors, you should only go there in case of emergency, provided you are not too sick.
5. This virus is deadly but still not too scary, except that sometimes it actually leads to a global disaster.
6. Gloves won't help, but they can still help.
7. Everyone needs to stay HOME, but it's important to GO OUT.
8. There is no shortage of groceries in the supermarket, but there are many things missing when you go there in the evening, but not in the morning. Sometimes.
9. The virus has no effect on children except those it affects.
10. Animals are not affected, but there is still a cat that tested positive in Belgium in February when no one had been tested, plus a few tigers here and there…
11. You will have many symptoms when you are sick, but you can also get sick without symptoms, have symptoms without being sick, or be contagious without having symptoms. Oh, my God.
12. In order not to get sick, you have to eat well and exercise, but eat whatever you have on hand because it's better not to go out, well, but no…
13. It's better to get some fresh air, but you get looked at very wrong when you get some fresh air, and most importantly, you don't go to parks or walk. But don’t sit down, except that you can do that now if you are old, but not for too long or if you are pregnant (but not too old).
14. You can't go to retirement homes, but you have to take care of the elderly and bring them food and medication.
15. If you are sick, you can't go out, but you can go to the pharmacy.
16. You can get restaurant food delivered to the house, which may have been prepared by people who didn't wear masks or gloves. But you have to have your groceries decontaminated outside for 3 hours. Pizza too?
17. Every disturbing article or disturbing interview starts with " I don't want to trigger panic, but…"
18. You can't see your older mother or grandmother, but you can take a taxi and meet an older taxi driver.
19. You can walk around with a friend but not with your family if they don't live under the same roof.
20. You are safe if you maintain the appropriate social distance, but you can’t go out with friends or strangers at the safe social distance.
21. The virus remains active on different surfaces for two hours, no, four, no, six, no, we didn't say hours, maybe days? But it takes a damp environment. Oh no, not necessarily.
22. The virus stays in the air - well no, or yes, maybe, especially in a closed room, in one hour a sick person can infect ten, so if it falls, all our children were already infected at school before it was closed. But remember, if you stay at the recommended social distance, however in certain circumstances you should maintain a greater distance, which, studies show, the virus can travel further, maybe.
23. We count the number of deaths but we don't know how many people are infected as we have only tested so far those who were "almost dead" to find out if that's what they will die of…
24. We have no treatment, except that there may be one that apparently is not dangerous unless you take too much (which is the case with all medications). Orange man bad.
25. We should stay locked up until the virus disappears, but it will only disappear if we achieve collective immunity, so when it circulates… but wait...we must no longer be locked up for that?
I think the current fatality rate may be underestimated since there are many people who are not tested and the fatality rate could also vary from country to country due to many underlying reasons. However, we can say the fatality rate of COVID-19 is at least 10 times higher than the usual flu. I hope when the pandemic over and data comes from all corners of the world we can definitely know the exact fatality rate.
Based on Antibody testing in New York, USA, the actual mortality is 10 times less than based on COVID-19 cases based on RT-PCR test results
https://www.ny1.com/nyc/all-boroughs/news/2020/04/23/governor-cuomo-daily-coronavirus-update-with-first-antibody-test-results
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