From simple to stupid

Epidemic: from the Greek, epi- (upon) + -demos (the people)

Pandemic: from the Greek, pan- (all) + -demos (the people)

Pandemic (according to the WHO): from external pressure and internal weakness, highly-virulent + "justified" panic + all + the people

The definition of a pandemic used to be simple: a worldwide outbreak of disease in excess of what would normally be expected (a global epidemic).  

The WHO even came out with a definition of worldwide spread (community transmission in 2 or more WHO regions).

But now, apparently, the WHO intends to change the definition of a pandemic from simple to stupid.

Bowing to pressure from member nations, the WHO is (according to the New York Times) going to change the definition to include the severity of disease, and will probably do so in such a way that the current H1N1 outbreak will never count as a pandemic (unless it becomes more virulent, which it very well might).

Now, you may remember that we've had three pandemics in the last century, one in 1918, one in 1957 and one in 1968... or, at least, that used to be true.  If this new definition goes into effect as described, we'll have to erase those last two from the list, because they were no more severe than this new H1N1 strain appears to be right now.

Whether a given outbreak is a pandemic or not is a separate question from how severe that pandemic is.  

If the WHO thinks a severity scale would be useful, then by all means they should create one. There are some good arguments against using a severity scale (flu viruses evolve so quickly, severity varies between and within countries, etc.), but it's possible a severity scale would help countries and communities to better plan for and respond to a pandemic... but the role of a severity scale should be to better describe an existing pandemic, not to determine whether an outbreak is a pandemic.

If the WHO goes through with this, there will be two definitions of a pandemic: One used by epidemiologists and other public health professionals, and one used by the WHO --because the WHO's new idea for a definition doesn't make any rational sense.  By setting up such a situation, the WHO will be undercutting its own credibility in a time when its ability to lead is more important than ever.

Instead of caving to the pressure of politicians from the member nations who feel that declaring a pandemic would cause "unjustified panic," the WHO should be using this as a teachable moment, to educate the public about what a pandemic is, what can be done about it, and why panic is never a justified reaction regardless of severity.

   

Suspected H1N1 in Indonesia

Apropos of my last post:

The Jakarta Post is reporting the first suspected case of H1N1 in Indonesia.  

The patient was identified by thermal scanning in the airport at Surabaya after arriving from Hong Kong, and is being treated in an isolation unit at a nearby hospital.  H1N1 infection has not yet been confirmed.

Indonesia is epicenter of the H5N1 epidemic in humans.  Not only is it the country with the most H5N1 infections to date, it is also home to the deadliest version of the virus.  The most recent official numbers* from Indonesia are 115 dead out of 141 cases, for a case fatality rate of 81.6%.  

*As you can see here, the WHO hasn't received official reports of any cases at all this year, despite the fact that we know the disease continues to occur in Indonesia, so any recent changes that might be occurring in the spread or virulence of the virus would not be reflected in these numbers.

If you're interested in (necessarily) unofficial reports of suspected cases and the latest news on H5N1 avian influenza in Indonesia, check out Bird Flu Information Center. 

Morbidity vs. Mortality

A Wall Street Journal article by Ron Winslow and Avery Johnson opines that a deadlier strain of flu virus would overwhelm the US healthcare system.

Sadly, it won't even take a deadlier strain to accomplish this.  Even if every single person who gets the virus recovers, a pandemic will cause a surge in the number of people sick enough to require hospitalization.  And that alone will wreak havoc on our healthcare infrastructure.  

We have, essentially, zero excess capacity in our healthcare system tpday.  I was involved in a full-scale emergency response exercise a few years ago and the local ambulance company did not expect to have any ambulances to spare for use in the exercise.  (They did eventually manage to find exactly one, but the real response to such a disaster would have called for many more.)

When I was helping the same health department with their pandemic response plan, we polled the local nursing homes to see what they had in terms of excess beds and respirators.  The answer was, "none to speak of."  --And hospitals are the same way.  

Severe economic pressures force these organizations to grow leaner and leaner all the time, to trim excess capacity wherever they find it.  And we haven't developed any worthwhile incentives to reverse that trend.

So people don't have to die in large numbers in order to overwhelm our healthcare system; they just have to get sick enough to require care.  Indeed, the sad truth is that those who die during a pandemic may use up fewer "bed days" than those who get sick, but pull through. 

Most hospitals right now couldn't deal with the results of a bus crash by themselves.  In order to meet the needs of an influx of patients like that, hospitals rely on their ability to transfer (or divert) patients to other nearby hospitals.  During a pandemic, however, this won't be an option, because those nearby hospitals will be equally overwhelmed.

Like many others who are looking at this problem for the first time, the authors of this article are putting an undue emphasis on mortality (death) versus morbidity (sickness) when it comes to the effects on the healthcare system.  In many ways, mortality is the most important thing about a pandemic.  It's certainly what worries me the most on a personal level.  But when it comes to the healthcare arena, it takes a back seat to morbidity.  

Because the thing that's going to transform the healthcare infrastructure from a moderately well-oiled machine into just a greasy pile of slag isn't the number of people who die, but the wholly unmanageable number of people who get sick.

Too soon to say

Suddenly, stories like this one abound, implying that the outbreak of H1N1 Swine Flu may not be such a big deal after all.

Of course, we all hope it turns out not to be a big deal, but as they finally got around to mentioning in paragraph 5 of the new article, it's "...too soon to be certain what the swine flu virus will do."

We are so early in this outbreak that we really don't know much about the epidemiology of this virus at all.  

• How many people have the disease?
• How many people have died?
• How readily is it transmitted from person to person?  
• What risk factors are there for infection (does it spread well among people crammed into the same airplane for several hours, but poorly in more open settings; are smokers or the elderly or some other group more likely to catch it)?  
• How lethal is the virus to those who catch it?  
• Who is most at risk of severe disease?
• When it does kill people, is it the flu infection itself (primary viral pneumonia) that causes death or is it secondary bacterial pneumonia that moves in after the flu virus is gone?
  

And it will be awhile before we have many of the answers.  In the UK, they are waiting for the results of more than 600 tests for the virus.  Mexico has a backlog of over 35,000 samples waiting to be tested, and their total number of confirmed cases shot up by nearly 250 overnight to 397 as a result of additional testing (not necessarily correlated to any new cases).  In the US, it's taking 4 days to get test results, which -with a virus that has only a 24 to 96-hour incubation period- means that our picture of confirmed cases here at home is far behind the times, as well.

And all that only goes to the epidemiological situation now.  The situation is likely to change over time, as the virus mutates.  In the case of the 1918 Pandemic, for instance, the first wave of infections spread around the world in the spring, and it was pretty mild.  It wasn't until the fall, when the next wave of infections struck, that the virus became so frighteningly lethal.

So I'm very pleased that the CDC, the Department of Health and Human Services, and the Department of Homeland Security are all continuing to take the situation very seriously and are doing an excellent job of letting the public know what we do and don't know.  

Dr. Besser, Acting Director of the CDC, has done a particularly good job of communicating the expectation that the government's response, the guidance to the public and the guidance to healthcare professionals will all continue to change as the situation evolves --and that that's a good thing.