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.

   

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.