In a rare piece of good news about Covid-19, a team of infectious disease experts calculates that the fatality rate in people who have symptoms of the disease caused by the new coronavirus is about 1.4%. Although that estimate applies specifically to Wuhan, the Chinese city where the outbreak began, and is based on data from there, it offers a guide to the rest of the world, where many countries might see even lower death rates.

The new figure is significantly below earlier estimates of 2% or 3% and well below the death rate for China based on simply dividing deaths by cases, which yields almost 4%. While it is still higher than the average 0.1% death rate from seasonal flu, it raises hopes that the worst consequence of the coronavirus will be uncommon.

Cutting against that optimism is the expectation that, because no one was immune to the new virus, “the majority of the population will be infected” absent the quick arrival of a vaccine or drastic public health interventions such as closing public places and canceling public events, the scientists conclude in a paper submitted to a journal but not yet peer-reviewed.

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The expectation that a “majority” of a population will become infected reflects a worst-case scenario about who encounters whom, something modelers call “homogeneous mixing.” But even the more realistic assumption that not everyone mixes with everyone else means that “at least a quarter to a half of the population will very likely become infected” absent social distancing measures or a vaccine, conclude Joseph Wu and Kathy Leung of the University of Hong Kong, leaders in the modeling of infectious diseases, and their colleagues.

The Covid-19 pandemic is sparking efforts to calculate how deadly this new disease is. One measure is called a case fatality rate. While the formula is simple, it’s difficult to get a precise answer.

The better news involves fatality rates. To calculate those, the researchers used data from Wuhan, especially the age distribution of 425 early cases and 41 early fatalities there.

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The chance of someone with symptomatic Covid-19 dying varied by age, confirming other studies. For those aged 15 to 44, the fatality rate was 0.5%, though it might have been as low as 0.1% or as high as 1.3%. For people 45 to 64, the fatality rate was also 0.5%, with a possible low of 0.2% and a possible high of 1.1%. For those over 64, it was 2.7%, with a low and high estimate of 1.5% and 4.7%.

The chance of serious illness from coronavirus infection in younger people was so low, the scientists estimate a fatality rate of zero.

As physicians and researchers have seen since the start of the outbreak, many infected people never become sick. As few as 14% of people in Wuhan with early coronavirus infections were being detected, said epidemiologist Jeffrey Shaman of the Mailman School of Public Health at Columbia University, who led a study published on Monday in Science on undocumented coronavirus infections.

“I think there are many more than the [nearly] 70,000” confirmed Covid-19 cases in Hubei province, Shaman told reporters.

That means the “infection fatality rate” — deaths among people who have the virus but might or might not show disease symptoms — is even lower than Wu and his colleagues calculate.

Despite Wuhan’s heroic efforts to treat patients, the suddenness of the epidemic overwhelmed hospitals there, much as it has in northern Italy. In countries that got more advance warning and prepared better, especially if social distancing succeeds in “flattening the curve” enough to dampen what would otherwise be a tidal wave of Covid-19 cases, the death rate is likely to be lower still.

“Fatality risk estimates may not generalize to those outside of [Wuhan], especially during subsequent phases of the epidemic,” Wu and his colleagues write. “The increasing availability of newer, and potentially better, treatment modalities to more patients would presumably lead to fewer deaths.” That’s true even within China, they find: “To date, the death-to-case ratio in Wuhan has been consistently much higher than that among all the other mainland Chinese cities.”

Lest anyone be tempted to downplay the threat, the scientists caution that Covid-19 is on track to infect millions of people. If social distancing fails to dampen the number of cases at any one time, overwhelming health care systems, the death rate would be higher.

  • If we tested everybody that got sick for the offending microorganism/s, and tallied the numbers each year, we would find epidemic-level illness and death.
    “I only listen to 3 people: Zarathustra, the Dalai Lama, and Hillary Clinton” (me)

  • Or maybe we aggressively quarantine and curfew the at-risk population, maybe the 250 million of us who aren’t high-risk go out of our way to protect and care for the high-risk among us, until the Wuhan flu dies out on its own, rather than crater the economy and curfew 300 million Americans.

    • Right. But the bad politicians care more about themselves and are trying to take full advantage of this misfortunate situation, they are trying to cause the most damage possible, remember this is the year of elections. Bad demonrats how dare they do that to us 😢

  • In the beginning of this virus the only people to be tested were those who were so sick that they had to be admitted to the hospital. Of course the death rate was higher. If we tested for flu only when the person was so sick that they had to be admitted to the hospital, the death rate would also be higher. The regular flu has already killed 13,000 in the USA while this new virus has killed less than 300. People, RELAX. We are letting this thing crush our economy. The dangers of this will be much more severe than the dangers of this particular virus. Just wash your hands and hope you don’t catch the flu.

    • Well John, the key different with COVID-19, and why scientists and governments around the world are universally extremely concerned is because not everyone gets the the regular flu. Almost everyone will get COVID-19.

      Mortality rates of the regular flu are quite terrifying if you applied it to the entire population, and COVID-19 is even more likely to cause death in patients.

      Yes, it primarily effects the elderly. But they fought wars for you, all you need to do is not spread disinformation and stay at home for them.

    • Chris, your comment implies that Covid is killing people who otherwise would not have died. Did you know that over a million Americans over 45 years old died of cardiovascular diseases, influenza and pneumonia last year? Are you sure these aren’t the very same people this virus is killing? Seems to me that the media/politicians have decided that it’s no longer okay for anyone to die. I’m good with that since I like my life and recently decided that I’d like to live forever too.

  • I don’t share your optimism nor understand how the situation in Wuhan translates to the rest of the world?? At this precise moment the world has a total of 226 313 corona virus cases reported, from these 9 283 ended in death – that’s a mortality rate of 4.1%!!! Also, out of the of 226 313 cases, 95 114 are closed, from these, 85 831 people recovered, the rest died. That means that of the closed cases, 9.75% are deaths!!! Not very good odds!!!!
    Coming back to Wuhan, there is no doubt that the Chinese government acted too late. They down played the situation and denied it’s severity (in truth, much like our government in the US!!!). After they recognized how serious the situation was, they applied draconian measures to contain it. Being a dictatorship, they had no problem what so ever in completly putting aside civil liberties to do what they though needed to be done. In western democracies this is significantly more complex to do.
    I personally believe that the situation in China and the West can not be compared. They are two very different realities.

    • It is not that simple to take lump sums. There are too many factors by region and if you knew anything about epidemiology, you would realize how complex each area would be. It is people like you who are causing mass hysteria.

    • Paulo. I agree with you in that you need to look at completed cases. For completed cases the death rate is about 9.8% world wide which is skewed heavily by China. But in Italy and Spain, that rate is over 40%. In South Korea, the rate is only about 4.5%. I am not sure the raw numbers are very reliable. The death numbers are probably the most accurate but recoveries may be under reported and total cases vary based on how good a job a country is doing in testing. In Korea, which is doing a lot of testing, there are about 168 cases per million in population. In the US, that number is only 29 due to lack of testing.

    • KJ – Did you take the time to read my post?! What you are saying is exactly my point!!! You point out that “there are too many factors by region…” and rightfully so. The stats from Wuhan are from Wuhan, they do not reflect the story world over.
      As for causing mas hysteria, perhaps you’re right but whether you like it or not, these are the numbers. They don’t focus on a specific region (which can have a higher or lower mortality rate) they are worldwide. The top 13 countries with the highest official count of infections have mortality rates as low as 0,3% (Austria and Germany) and as high as 30,9% (The Netherlands) so it’s preferable to look at the global picture, not specific regions. If I wanted to create hysteria I would have focused on the Netherlands or Italy, or I would have focused on the fact that mortality rate have been increasing steadily every day for the past weeks, or even the fact that the percentage of deaths in closed cases has risen from 6% early last week to 10% now!!!
      If you feel comfortable with these odds good for you, personally I don’t!!! Unfortunately, I have no idea whether I live in a region with 0.3% mortality or 30.9%!!!
      Perhaps you belong to the group of people that a few weeks ago was saying that “this is nothing to worry about”, that “seasonal flews kill much more people” or even “that everything is under control”.
      Oh, one more thing, I’m sure you are an expert in epidemology, I personally am not (nor do I try to be) but you know what, you don’t need be one to crunch the numbers!!!

  • Bottom line is, we need to get a vaccine and start giving it to people immediately – no “Stage X trials” – just start giving it to everyone over 60 who is willing to take it, as fast as you can make it, as long as it is made according to good theory. Do this with multiple vaccines and see what works.
    The cautious medical establishment generally serves us pretty well, maybe – I do not know, it requires too much education – but in these circumstances, we have to try multiple routes concurrently. FAST.

    • You, sir, should never be allowed to be in charge of anything in your life. Like, anything. The reason why there is a defined vaccine (and all medications really) testing process, and they don’t just throw random concoctions at people to see what sticks, is that early stage (undeveloped) vaccine varieties can be more deadly and dangerous than the disease they are attempting to vaccinate for. Your approach is like those suggestions about solving invasive species issues by introducing another invasive species to eat the first one. You have shown a complete lack of understanding of anything associated with this topic. Good luck with life.

    • You cannot just pass out a “new drug” without testing, this could result in more deaths or could cause other, significant health issues. Back in the day, even with clinical trials lasting for years, drugs were released to the public that killed them (diabetic drugs) or caused death related to significant bleeding (VIOX).

  • I have a humble suggestion. Let’s take ideas people have seriously instead of mocking them.

  • Why does China want to hide the fact that the virus started there..and why do they try to hide any truth from their own people?

    • It is an interesting question. Certainly, the initial slow response of the Chinese Government is embarrassing to Xi. And it also might interfere with their foreign policy with other nations.

      It is interesting that there are elements in the U.S. who are supporting this revisionist attempt by the Chinese Government.

      Having an enemy is usually helpful in maintaining social unity so the U.S. is now the enemy.

      We and others are reimporting Covid 19 into China and many on this message board are ok with that as they urge quarantining the elderly and allowing COVID-19 to become another seasonal flu.

      I am astounded by the selfishness of so many in the U.S. It shows how low we have become. What kind of person treats their parents that way?

  • so ‘social distancing’ is suddenly a virtue, whereas, ‘keeping to one’s self’ is considered a social vice. the more you listen to experts, the less you know.

    • There are too many people who base their opinion solely base on their situation and not on humanity as a whole. My thoughts and concerns here actually do not reflect my own situation. While not wealthy, I am set up so my family can absorb the hit. How it will effect business in the future, I don’t know. I am concerned for the less fortunate who cannot absorb just stopping everything for who knows how long. So instead of putting focus on the groups of people with the most deaths, lets just seclude all 7.7B people in the world and hope the virus goes away. That is so much better. There are too many variables in the world for that to be realistic. Today’s actions are designed to let our poorly equipped medical system cope with projected cases in the short term. It is concerning that people either think the virus will go away with the actions being taken or a vaccine will magically come in a month. Lets say we all stay in for 3 months and sacrifice the economy and all the real people that will be sacrificed because they cannot afford to live (without a paycheck) and we put a good halt on the virus. How many people will there be with the virus left in the world? It won’t be zero. Out of 337B that is nearly impossible. How long does it take until we have to do round 2, then 3 when it makes it’s way back? Can the world really absorb that? Time will tell, but the past does not reflect the outcome of current actions will eliminate the virus, only slow the spread at a very high cost to humanity with these unprecedented actions. A vaccine or antiviral are the real solutions. A vaccine will take well over a year, just to get through testing. There are some potential, already FDA approved antivirals, which fingers crossed, may bring help to those who get hit hardest by this virus. If people especially in the lower middle class cannot earn a paycheck for a long period of time, we will start seeing children going homeless and in the worse case scenario dying as a result of the economic impact. Now they are a factor in the death rate too, but by choice. Small and medium sized businesses which drive our economy will fail and the trickle down will impact people in ways nobody can completely understand at this point. The impact outside of the virus needs more consideration. Whats the point of of trying to save 1-5% of the world if were going to make life miserable and impossible in many cases in the process?

  • I think it is very important to emphasize that this is the Symptomatic case-fatality risk. That is to say that this mortality rate doesn’t even include estimates for infections that don’t develop symptoms. Including those numbers would drive the mortality rate even lower. Please see the following related manuscript awaiting peer review and publishing:

    https://www.medrxiv.org/content/10.1101/2020.03.06.20031880v1

    or search for:
    “Estimating the scale of COVID-19 Epidemic in the United States: Simulations Based on Air Traffic directly from Wuhan, China”

    There is also a Los Angeles Times article which adequately explains the manuscript in layman’s terms:

    https://www.latimes.com/science/story/2020-03-10/us-coronavirus-cases-far-above-official-tally-scientists

  • Based on this study, wouldn’t it be more efficient for the USA and possibly the rest of the world to isolate only the people who have underlying medical issues or are 65 and older and let the rest of the population go on as normal as their death rate appears to be closer to the flu rate. Elderly and Ill people living with the younger folks would be moved out of their homes into temporary facilities and cared for. This way the rest of the population gets the virus and it dies out. It probably is less costly and disruptive as this isolated group typically doesn’t work so the money infusion would be to care for this displaced group only.

    • Richard Wagner that has been a nagging question of mine since they requested social distancing.

    • Well said and backed up with data! There should be a vigorous debate on this -protect the old and the weak and let the rest of us shoulder the pandemic without major risks. The hard part is how best to protect the old and the weak.

    • This is what I have been saying for over a week now. The people who are least affected drive the economic system. Those at high risk are mostly retired and extreme measures would leave the economy intact. Protect the most at risk and pay for it by keeping the economy robust. Sure there will be deaths outside of the high risk category, but sadly, that is inevitable any way you look at it. I also don’t think it is possible to isolate 337M in the US. Not everyone will play along, but the most at risk will. It’s so logical to me. I’m not concerned for my wife and kids here. I’m concerned for those who will be affected by the economic shutdown as well as the high risk who are getting a rough deal with this virus. I can’t help but to think that more will die from economic collapse than the virus in the end the way were headed. I hope I am wrong there.

    • My husband and I were discussing the same thing before reading the article and now not sure why this was not the decision of the governments of the world – protect the at risk and let the rest of us go about our lives.

    • One wonders about the thinking ability of Americans.

      Who are the at risk? There are more over 60 at risk but many younger people are also having problems with this virus.

      What do you do with everyone over 60? That is a lot of people. Can their children visit them? There are many over 60 in the work force. I am a lot older than 60 and run a business and am an elected public official.

      Do we want Americans to ever be allowed to travel again? If other nations stop this virus but it became a regular part of the environment here in the U.S. Americans will not be allowed to travel outside the U.S. they will be banned.

      The doubling time of this virus unimpeded is four days. So excluding the older folks the hospitals will be overwhelmed very soon and what might be fairly mild cases will be more problematic.

      And how do you protect the older more vulnerable? Are they allowed to see a doctor? Will they ever be allowed to go to a restaurant.

      Some people are very selfish and many such post here. I find it disgusting. But that is what this nation has come to.

    • I agree with much of what has been said here.
      In one of our local communities, they shut down the schools earlier than the rest because 60% of the students’ primary caregiver is over the age of 60. This adds another layer of complexity to mandating a solution.

      I think the solution to this is simple: Allow kids in high-risk households to receive distance learning for 30-45 days. Let everyone else return to school. It will never fly because it’s unfair.

      Sigmund,
      I don’t understand the general point of your questions. It sounds like you are saying our current plan (social distancing for everyone which leads to economic crash) would allow you work, see your children, travel, see a doctor, visit a restaurant. I think what the commenter is trying to say is that right now, nobody can do any of those things and their proposal is to let anyone who wants to accept the risks of living be allowed to do those things. The rules are simple, each individual makes choices based on their risk tolerance.

      Do you believe that life is better as a whole if freedom to choose is given to all individuals? Isn’t that the foundation of America? Is freedom to choose more important than freedom from harm?

    • Richard Wagner – I had the same thought tonight – the young folks seem to have so few serious cases – give them all the virus, on a staggered basis, and let them all be sick, while isolating the old folks until all the young have caught it and are immune (we hope).

      But while it might make sense in theory it seems nearly impossible logistically, knowing how people actually act, to bring it about. And highly traumatic to a lot of people – the young child who is being raised by her grandparents because her parents died, or got on drugs, went to prison, whatever the reason .
      Or I can think of a thousand other situations where it would be very difficult.
      All that said, if we are for sure looking at an extremely high death rate among old folks, and there was no hope of antivirals or vaccines, I would say we might need to do it.
      I would support a 6 week national shutdown, but the problem is, we won’t get it. Too many people will not obey it, we even have Congressman saying to do the opposite – go out and party if you are “healthy” – meaning asymptomatic right now, a lot of our politicians have no damn idea of how viruses work, but that does not seem to inhibit them from giving public health advice.

      I think our best hope is to do widespread experimental treatments and vaccines ASAP on our own population. A vaccine seems pretty straightforward from everything I read – this talk of it taking 18 months, even a year is the single thing that upsets me most. I will volunteer – no, I will beg, borrow or steal, any reasonable experimental vaccine.

    • This is a consideration. Assuming the numbers above are all correct and it worked, we’d only lose 600,000 people between the ages of 20 and 64. Seems like a good tradeoff to save the elderly! My only concern is, will they die fast enough? They’ll be taking up a bunch of ICU beds until then. We need those beds for the elderly. Maybe we can restrict ICU beds to elderly and things that aren’t COVID-19 only? Keep all the COVID-19 people in some other area. Thoughts?

      – Jon Swift

    • There are reports coming out now that in the USA 20% of hospitalizations are of people under the age of 44 with many of those needing ICU beds. Italy and France have reported similar. So it may not be the best course of action to just let it run rampant through the younger population as they may be more vulnerable than we first assumed.

    • Do those reports indicate whether any of those under 44 had other underlying health issues that might’ve contributed to their hospitalizations, or that might’ve exacerbated the effects of the Wuhan flu? If not, then it’s journalistic malpractice, IMO.

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