Swine H1N1 flu case fatality rate is edging higher worldwide
Scott McPherson
in Politics and government, Popular Culture, influenza and infectious diseases
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8 Comments
I don't know how many of you have caught this or done the math, but the case fatality rate (CFR) from swine flu has actually increased, at both global levels and within the United States.
The published global CFR in late June was plugging along at .002, while the US CFR was at .0045. Now, the US CFR is .0056, and the global CFR is at .0045. So the world has caught up with America in terms of its death rate, and the figure of .0045 places this pandemic squarely within the HHS Category Two pandemic status. But the threshold to Category 3 status is .0051. For the past two weeks, the US CFR has exceeded the Category 3 benchmark. Like the hurricane that spawned this HHS analogy, those winds -- and deaths -- have to be sustained. The next few weeks will tell us if we are seeing a drop in the CFR, or if the numbers are holding steady. That may also signal the waning of the pandemic's first wave.
These death numbers do not sound large until you look at large numbers. If the current CFR holds, by the end of the pandemic, we could be looking at over 400,000 dead in the United States alone. In Florida, for example, the final death toll could reach 30,000.
This is probably why the WHO has chosen its words very carefully when describing this pandemic as "moderate" and not as "mild."
How is this possible, you ask? Swine H1 is "mild," the public health authorities are telling us! You are even hearing the words "no worse than seasonal flu" mentioned!
I would answer this way: First, read Dr. Kawaoka's analysis of swine flu in today's/tomorrow's papers. Second, re-read my blog about totally botched risk communication, and Google/read Dr. Sandman's similar remarks about recent botched risk communication. Third, remember we are in the beginning stages of a global health crisis that will take at least eighteen months to finally play out.
Pandemics are not for institutions with ADD, nor are they for institutions who like quick resolutions at the end of a 60-minute show. Nor are they for institutions who demand happy endings, unless you count the conclusion itself as happy. They are slow, historic, and life-changing events. We should treat them and respect them as such.
Reader Comments (8)
Hi Scott - Good to see you posting. This will indeed be a long process.
I wish to invite you and your readers to read my pandemic flu blog novel, 'American Fever: A Tale of Romance & Pestilence,' now online at americanfeverbook.com
The site is FREE.
I've worked on it for years, helped in no small measure by you and the other members of Flublogia, which my blogger tours on Day 5, appearing online Tuesday. A certain Englishman you and I both admire will appear halfway through my text....
Keep blogging.
Thanks, Peter
Yep. This seems to have been the general direction of news for the past month or so. However, I do think this will be different from 1918. People have different set of health issues, nutrition, work environments, travel, etc. We're in a radically different context now. Even if we have a virus that is biologically just as severe as 1918, for better (and worse) we'll probably experience it in a very different way.
My understanding is that the CFR is calculated by the number of deaths divided by the number of reported cases.
But if many more people than we realize currently have somewhat "mild" cases of H1N1 and aren't going to the doctor (unreported cases) doesn't that change things?
My community currently has a number of people with influenza like illness, likely H1N1. However many of these folks are staying home and taking care of themselves without necessitating a doctor visit, because the symptoms are relatively mild. Especially my friends without health insurance.
Help. I'm a dummy. Please explain how this may or may not influence the CFR.
Now Singapore is entering into a phase with ciritcal patients, 3 currently in Intensive Care Unit.
You can extract information on Singapore H1N1 situation from this government site:
http://www.h1n1.gov.sg/homepage.htm
Singapore is like a canary in the mine, as it has a good healthcare system and good preparedness gained from the previous SARS crisis. Moroever it is in tropical climate. Still Singapore has 50 hospitalised cases, with 3 in intensive care unit.
2 was with previous conditions, 1 is a pregnant woman without prior conditions.
Now Singapore has dropped its border screening, and we would expect more cases soon.
Cases in Hospital
Last updated on 15 July 09
There are 50 confirmed Influenza A (H1N1-2009) cases in hospitals, including 3 in ICU.
The 51-year-old patient with multiple co-morbidities (diabetes, hypertension) is still in ICU in CGH, though in stable condition.
New ICU cases
A 45-year-old woman with multiple co-morbidities (diabetes, hypertension, hyperlipidaemia, and peripheral vascular disease) is now in critical condition in SGH ICU. She had sought treatment at SGH Emergency Department on 4 July 09 after 2 days of vomitting and diarrhoea, and was admitted. Patient was also on immunosuppressants as she had undergone a kidney transplant in 2006. Her condition deteriorated and she was transferred to ICU on 12th July. Laboratory tests confirmed that she was also infected with H1N1.
A 22-year-old woman who is 24 weeks pregnant was admitted to KKH on 13 July when she developed pneumonia and was tested positive for H1N1 at a private hospital. On 14 July, she was transferred to ICU for closer monitoring as her requirement for oxygen increased. She has no underlying medical conditions.
Public Hospital Hospitalised (in ICU*)
Alexandra Hospital 2
Changi General Hospital 14(1*)
KK Women's and Children's Hospital 9(1*)
National University Hospital 12
Singapore General Hospital 4(1*)
Tan Tock Seng Hospital 2
CDC 2 7
Total 50(3*)
*number of patient(s) in Intensive Care Unit
Chris,
See my post on Britain's new and sudden revision upward of potential deaths.
If CFR has been calculated based on numbers of confirmed cases rather than an estimate of the total number of cases, the apparent CFR goes up when testing of mild cases goes down.
Simply put: at the beginning of the epidemic most suspected cases were tested. Now there are many more cases and there simply aren't the resources to test each of them. So only the more severe cases are tested. The result: the cases we know about are more severe. So CFR looks worse.
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19255
CFR = 0.000006 - 0.00004
In finding the CFR, the denominator must be confirmed cases while the numerator is obviously number of recorded fatalities of lab confirmed cases as is being calculated by the Union Ministry of Health and family Welfare,Government of India. India has posted the CFR for H1N1 at 3.82% as on 10 January 2010 [total Lab Confirmed Cases: 27712; Deaths : 1059].Done this way, there shall be little discrepancy between respective national CFR.Arguably, this method is by far superior and most rational. We follow this routinely in epidemiological calculations.
Dr TARIQ WALI, Epidemiologist-Nodal Officer, DEIT
IDSP, Government of India, Bulandshahr INDIA.