Discussion - Estimating the CFR for 2019-nCoV

[Ronan Kelly]

The only problem with the Italian figures is a report on 2/28 that said they were changing the counting system to exclude the asymptomatic cases even if they were positive.

"The idea of ​​the ministry is therefore that of not communicating any asymptomatic cases to the international bodies that deal with the epidemic, that is, people who are positive to the swab but do not have any health problems. These infected represent between 40 and 50% of all cases reported at this time. "

https://www.repubblica.it/cronaca/2...io_esclusi_i_positivi_asintomatici-249765660/

 

[Ronan Kelly]

I've been looking at the 705 positive cases from the Diamond Princess that remained in Japan. 6 have died (0.85%), but 36 were listed as in serious condition, so that number may yet increase.

 

[kiwibird]

Shiloh
Editor, Senior Moderator

• Join Date: Feb 2008
• Posts: 55788

• #99

Yesterday, 01:23 PM
Source: https://www.ansa.it/canale_saluteebe...6910a141e.html

821 are infected in Italy with Coronavirus. The new data was provided by Commissioner Angelo Borrelli during the press conference to the Civil Protection. The number also takes into account the 21 victims - 4 more than yesterday - and the patients recovered. "Today's deceased are over eighty and one over seventy. I would like to specify that they did not die from coronavirus or as a consequence. This is a job that the Istituto Superiore di Sanit? will do. When you have the data, you will communicate it to us," said Borrelli, during the press point at the Civil Protection headquarters. "The important fact - he added - is that half of the infected (412) are people who are asymptomatic, or with very slight symptoms and therefore do not need hospitalization. They are in fiduciary home isolation. Another 345 people are hospitalized with and 64 are hospitalized in intensive care. " "The assistance to the population continues, on Monday the post office will reopen in some municipalities to pay pensions. In the red areas, life will continue regularly".

If you look at the figures from the 28th, yesterday, and we believe they will be accurate - then the 821 with a CFR of 2.5% would give 20.5 and it unfortunately shows 21 victims.
Perhaps the confirmed cases on the Diamond Princess were only recently infected?

 

[Laidback Al]

There several current estimates for the case-fatality rate of COVID-19.

A. February 24, 2020
“Case-fatality rate 2.3%” Characteristics of and Important Lessons from the Coronavirus Disease 2019 (COVID-19) Outbreak in China

B. February 28, 2020
“The CFR outside of Hubei, although based on limited data, is much lower, likely no higher than 1% to 2%, “ COVID-19—New Insights on a Rapidly Changing Epidemic

C. February 28, 2020
“…the currently reported case fatality rate is approximately 2%” Covid-19 — Navigating the Uncharted

When discussing the CFR for COVID-19 in various countries, we need to consider the median age of a country’s population. As noted by the authors in A above, older people, usually with existing comorbidities, have a higher death rate. The table below presents the information on five countries outside of China with the highest number of cases. These countries account for about 78% of all COVID-19 cases outside of China. Among these countries, 77 people have died (through February 29, 2020), about 90% of all coronavirus deaths reported from countries outside of China.

While the current ratio of deaths to reported cases is not an accurate measure of the CFR in these countries, it is a rough proxy measure. As shown in the table, there are slightly higher ratios for countries with aging populations, although the high death rate in Iran is an outlier. The overall population pyramid in a country will have a skewing effect on the CFR for that country. However the current ratio of deaths to cases cumulatively in these five countries is at 1.7%, within the range suggested by the studies above.

 

[kiwibird]

Thank you Al and Ronan. I have been trying to find the ages and cannot account for 10 people.


22nd Feb 77 years and 78 years
23rd Feb 68 years
24th Feb 84 years, 88 years, 62 years, 80 years
25th Feb 84 years, 91 years, 83 years, 76 years
26th Feb 69 years
27th Feb 88 years, 88 years, 80 years
28th Feb 85 years, 77 years, 80+ years, 80+ years

Also there are sadly two further victims from the Diamond Princess, a lady in her 60's from Tokyo and an elderly Australian man, as well as the lady in her 70's also from Tokyo whom you noted here Ronan -

​​Ronan Kelly
Editor, Senior Moderator

• Join Date: Aug 2009
• Posts: 37587

#69
February 28th, 2020, 10:31 AM
About death of patient associated with cruise ship under quarantine at Yokohama Port
　Today, February 28, a cruise ship-related patient who has been quarantined at the Port of Yokohama has died. I pray for the soul of the deceased.
When reporting, please give due consideration to the privacy of the deceased and the bereaved.

Patient (5th death)
1 Outline

(1) Age: 70s
(2) Gender: Female
(3) Place of residence: Tokyo
(4) Basic illness: Hypertension, Diabetes

 

[Ronan Kelly]

There several current estimates for the case-fatality rate of COVID-19.

Thanks Al - great info. As the current cfr's are all being calculated with conf deaths/conf.cases they are all limited by the testing regime of the country involved which may or may not be missing milder cases. It seems to me that the South Korea has the most comprehensive regime right now and has selected an entire population of 200,000 church members that it is determined to test. As such it is reporting cases that other surveillance methods might be missing and has by far the lowest fatality rate of 0.5%. Similarly with Diamond Princess, a captured tested population, probably skewed to the older age group, which includes lots of asymptomatic people has a cfr of 0.85%. Both SK and DP numbers may increase as cases resolve, but these two give us a baseline minimum for the cfr. At a minimum, 0.5% of cases look likely to be fatal - 4 to 5 times the rate of flu. That should give anybody pause about the effect of a general outbreak in the US. I think that an overall infected fatality rate of 0.5-1% is more probable for this disease and that in itself will tax health care systems severely.

 

[Ronan Kelly]

Thank you Al and Ronan. I have been trying to find the ages and cannot account for 10 people.

Japanese press releases here if it helps: https://www.mhlw.go.jp/stf/houdou/index.html

 

[kiwibird]

Japanese press releases here if it helps: https://www.mhlw.go.jp/stf/houdou/index.html

Oh sorry Ronan - they were the ages of the Italian victims. I really didn't make that clear. But thank you for the Japanese ones.

 

[kiwibird]

The list of Dates and Victims ages is from the Italian thread. Apologies for the confusion.

 

[sharon sanders]

"Globally, about 3.4% of reported COVID-19 cases have died. By comparison, seasonal flu generally kills far fewer than 1% of those infected."

https://www.who.int/dg/speeches/det...the-media-briefing-on-covid-19---3-march-2020

 

[Vibrant62]

Do we have onset dates for DP cases? Does anyone know where these can be found? This is still probably the best epidemiological insight we are going to have at the moment. Also would be useful if we knew exactly what the passenger and crew age distribution was... I am guessing there will be more fatalities in the coming days, bearing in mind that the data suggests it is more usually a 2-3 week period from symptom onset to death? This data may also may be confounded if cases that have subsequently developed after passengers disembarked in Japan or returned elsewhere are not included in the original DP numbers (i know there have been some)

 

[kiwibird]

https://www.taiwannews.com.tw/en/news/3884830

TAIPEI (Taiwan News) — With much more data from outside of China now available, the World Health Organization (WHO) on Tuesday (March 3) raised its estimate of the average death rate for the Wuhan coronavirus (COVID-19) from 2 percent to 3.4 percent.

Before the disease spread significantly to the outside world, the WHO through most of February estimated the mortality rate to be around 2 percent. This was largely based on highly questionable statistics from China, which showed an average daily death rate that mysteriously never fluctuated far above or below 2.1 percent for weeks.

Many scientists have questioned China's death rate statistics, as they present a near-perfect prediction model rather than sporadic spikes and troughs. Melody Goodman, associate professor of biostatistics at New York University’s School of Global Public Health, told Barron's that a regression run on China's data on fatality rates yielded a near-perfect r-squared (measurement of variance) score of 99.99 percent, which she said is never seen with real data.

"I have never in my years seen an r-squared of 0.99. As a statistician it makes me question the data," said Goodman. She said that when it comes to public health data, a high score would be a 0.7.

Goodman added that "Anything like 0.99 would make me think that someone is simulating data. It would mean you already know what is going to happen."

By February 24, the WHO Director-General Tedros Adhanom estimated that the fatality rate in Wuhan ranged between two and four percent, while the death rate in the rest of China was 0.7 percent. He claimed that his team estimated that measures taken in the communist country had "averted a significant number of cases," without providing any specifics.

However, in the week since, the number of confirmed cases and reported deaths have skyrocketed in Iran, South Korea, and Italy, providing much more data from outside China. With this data in hand, Tedros on Tuesday (March 3) patted China on the back for lowering its number of cases and announced that 80 percent of the new cases outside of China had been reported in Iran, South Korea, and Italy.

Adhanom then dramatically increased the estimated average mortality rate, saying, "Globally, about 3.4 percent of reported COVID-19 cases have died," He then pointed out that this percentage is far higher than the one percent death rate for those who contract the flu.

According to The New York Times, in the U.S., the death rate for the seasonal flu is typically around 0.1 percent, not one percent as Adhanom claimed.

The WHO head then proudly proclaimed that "evidence from China" indicated that only one percent of cases reported were asymptomatic. Yet in Japan, as of Feb. 26, 19 out of 186 infected patients, or 10.2 percent, had not shown any symptoms, excluding passengers from the Diamond Princess cruise ship, reported Japan's Ministry of Health, Labour and Welfare.

 

[Ronan Kelly]

[h=1]Estimating the infection and case fatality ratio for COVID-19 using age-adjusted data from the outbreak on the Diamond Princess cruise ship[/h] Status: in-progress | First online: 05-03-2020 | Last update: 05-03-2020

Authors: Timothy W Russell*, Joel Hellewell[SUP]1[/SUP], Christopher I Jarvis[SUP]1[/SUP], Kevin van Zandvoort[SUP]1[/SUP], Sam Abbott[SUP]1[/SUP], Ruwan Ratnayake, CMMID nCov working group, Stefan Flasche, Rosalind Eggo, W John Edmunds & Adam J Kucharski.* corresponding author1 contributed equally

This study has not yet been peer reviewed. [h=2]Aim[/h]
To estimate the infection and case fatality ratio of COVID-19, using data from passengers of the Diamond Princess cruise ship while correcting for delays between confirmation-and-death, and age-structure of the population. [h=2]Abstract[/h]
Adjusting for delay from confirmation-to-death, we estimated case and infection fatality ratios (CFR, IFR) for COVID-19 on the Diamond Princess ship as 2.3% (0.75%–5.3%) and 1.2% (0.38–2.7%). Comparing deaths onboard with expected deaths based on naive CFR estimates using China data, we estimate IFR and CFR in China to be 0.5% (95% CI: 0.2–1.2%) and 1.1% (95% CI: 0.3–2.4%) respectively. [h=2]Main text[/h]
In real-time, estimates of the case fatality ratio (CFR) and infection fatality ratio (IFR) can be biased upwards by under-reporting of cases and downwards by failure to account for the delay from confirmation-to-death. Collecting detailed epidemiological information from a closed population such as the quarantined Diamond Princess can produce a more comprehensive description of asymptomatic and symptomatic cases and their subsequent outcomes. Using data from the Diamond Princess, and adjusting for delay from confirmation-to-outcome and age-structure of the ship’s occupants, we estimated the IFR and CFR for the outbreak in China. As of 3rd March 2020, there have been 92,809 confirmed cases of coronavirus disease 2019 (COVID-19), with 3,164 deaths [1]. On 1st February 2020, a patient tested positive for COVID-19 in Hong Kong; they disembarked from the Diamond Princess cruise ship on the 25th January [2,3]. This patient had onset of symptoms on the 19th January, one day before boarding the ship [2]. Upon returning to Yokohama, Japan, on February 3rd, the ship was held in quarantine, during which testing was performed in order to measure COVID-19 infections among the 3,711 passengers and crew members onboard. Passengers were initially to be held in quarantine for 14 days. However, those that had intense exposure to the confirmed case-patient, such as sharing a cabin, were held in quarantine beyond the initial 14-day window [3]. By 20th February, there were 634 confirmed cases onboard (17%), with 328 of these asymptomatic (asymptomatic cases were either self-assessed or tested positive before symptom onset) [3]. Overall 3,063 PCR tests were performed among passengers and crew members. Testing started among the elderly passengers, descending by age [3]. For details on the testing procedure, see [2] and [3].
...
https://cmmid.github.io/topics/covid19/severity/diamond_cruise_cfr_estimates.html

 

[Ronan Kelly]

A 7th Diamond Princess passenger from the 696 confirmed cases that stayed in Japan has died bringing the cfr in that cluster to 1%.

 

[gsgs]

are there any estimates about the CFR, when hospitals are no longer available ?
At the peak of a wave, in countries where they didn't contain it and which get a full wave.
It had been said that 20% of cases need hospitalisation and the lower end of estimates
of infected people was ~30% within 1 year . Assume 1/3 of these die because they are
not hospitalised that would give ~7%CFR and 6.5M deaths in USA within one year,
not counting the additional deaths from other diseases/causes due to interruptions
in health care and other areas.

is 1/3 realistic ? I'm usually counting that 1/3 of the listed severe COVID cases will die

 

[Ronan Kelly]

Adjusted age-specific case fatality ratio during the COVID-19 epidemic in Hubei, China, January and February 2020
Julien Riou, Anthony Hauser, Michel J Counotte, Christian L Althaus
doi: https://doi.org/10.1101/2020.03.04.20031104
This article is a preprint and has not been peer-reviewed [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.
AbstractInfo/HistoryMetrics Preview PDF
Abstract
The coronavirus disease 2019 (COVID-19) epidemic that originated in Wuhan, China has spread to more than 60 countries. We estimated the age-specific case fatality ratio (CFR) by fitting a transmission model to data from China, accounting for underreporting of cases and the time delay to death. Overall CFR among all infections was 1.6% (1.4-1.8%) and increased considerably for the elderly, highlighting the expected burden for populations with further expansion of the COVID-19 epidemic around the globe.
...
https://www.medrxiv.org/content/10.1101/2020.03.04.20031104v1

 

[Shiloh]

Why Korea's CFR is low: https://asiatimes.com/2020/03/why-are-koreas-covid-19-death-rates-so-low/

 

[Shiloh]

Covid-19 Is Nothing Like the Spanish Flu
A widely-cited stat about death rates seems to argue otherwise, but it's surely incorrect. So how'd it end up in the research literature?

Coverage of the novel coronavirus pandemic teems with monstrous and sometimes contradictory statistics. Among the most vexing figures flitting across our screens, and spreading via text and Tweet, is the case fatality rate (CFR)—the proportion of known infections that result in death. Early in the Covid-19 pandemic, World Health Organization officials announced an average CFR of 2 percent. Later on, they revised it up to 3.4 percent. In contrast, numerous epidemiologists have argued that the global case fatality rate is closer to one percent. These might seem like small differences, but when multiplied across large populations they translate to significant discrepancies in overall deaths.

Some experts have emphasized the difficulty of calculating the fatality rate of an emerging pandemic, explaining that current estimates are biased by a deficit of testing and by the lag time between onset of illness and death. Despite this counsel, news coverage and social media discourse has obsessed over CFRs and how they compare across pandemics throughout history. A popular refrain is that the new coronavirus has a frighteningly high fatality rate of at least two percent, which is supposedly comparable to that of the 1918 influenza pandemic, also known as the Spanish flu—one of the deadliest viral outbreaks in history. The truth is that this comparison is severely flawed and that the numbers it relies on are almost certainly wrong...

Read more: https://www.wired.com/story/covid-19-is-nothing-like-the-spanish-flu/

 

[JJackson]

Excellent article thanks Shiloh. I am glad to see a balanced piece explaining why CFR calculations are a nightmare and impossible to pin down at the very beginning of an epidemic, which is where we are now. The current crude CAR is 0.00% (to two decimal places) if containment fails 30% may be a fair guesstimate. How our hospital systems cope with that will be a major determination of an areas CFR, not even Wuhan has had any experience with that scenario and they had 40,000 HCWs come in from outside - when there was an outside.

 

[Shiloh]

Published 23 mins ago
Cruise ship data helps reveal coronavirus death rate: researchers
By Maxim Lott | Fox News
the coronavirus outbreak: Should I cancel my cruise? What precautions should I take?

Plan on taking a cruse during the corona virus outbreak? Here are some precautions to take.

Reliable data on coronavirus's death rate has been scarce, with early numbers coming from China.

But results from the cruise ship Diamond Princess could help provide a reliable estimate, medical researchers believe.

An examination of ship data concludes that widely-reported death rates are simplistic and too high, because people with mild symptoms often don't bother to come in for testing and don't get counted.

But on the Diamond Princess cruise ship, mild cases weren't missed, because every passenger and crew member was tested a month ago.

"It's really valuable data that we just wouldn't have otherwise, because all people were tested," Dr. Timothy Russell, a mathematical biologist at the London School of Hygiene and Tropical Medicine, part of the University of London system, told Fox News.

"The 3.4% death rate the World Health Organization has reported... there is criticism from nearly all scientists that's too high, because of the under-reporting of cases."

Read more: https://www.foxnews.com/us/cruise-ship-data-helps-reveal-coronavirus-death-rate-researchers