Going Where No Pan Has Gone Before
# 1904
The chart above, depicting the five categories of pandemics, comes from the HHS/CDC document: Interim Pre-Pandemic Planning Guidence: Community Strategy For Pandemic Influenza Mitigation In
Released Feb. 1st, 2007, this is the guidebook for how the United States will attempt to mitigate a pandemic.
If you haven't read this document, I strongly suggest that you do so. It is chock full of vital information about what measures will be taken to slow the spread of a pandemic. This document is available for download here in pdf format (approx 10mb).
Pandemics in the future will be categorized, just like Hurricanes. Mild pandemics will be category 1 or 2, while severe pandemics will be rated as category 4 or 5. People are used to these designations so they will require little explanation.
While these rankings will obviously be useful during the next pandemic, just like hurricanes, pandemics can fluctuate in strength. What might start out as a Category 1 pandemic, could rapidly intensify to a Category 5 event.
In fact, that's exactly what happened in 1918.
The first wave, in the spring of that year, was widespread but mild. It would not have registered higher than a Category 1 pandemic, had that scale existed at that time. When the influenza returned in the fall, it had mutated into Category 5 virus, killing tens of millions in a matter of months.
Of course, a severe Category 5 pandemic could just as easily diminish in intensity and end up as a Category 1.
Since a pandemic could last a year or longer, there will be plenty of opportunities for fluctuations in its intensity. And just as we saw in 1918, some areas may be harder hit than others.
The CFR (case fatality ratio, or % of infected that died) varied widely around the globe in 1918. In northern Europe, less than 1% of those infected died from the Spanish Flu, while in the United States, the death rate was about 2%.
While there was an absence of good record keeping in India back then, anecdotal reports indicate that the death rate there was in excess of 10%. And in the Fiji Island, supposedly 14% of those infected died. For many countries, numbers simply aren't available.
The point is, part of the world could be experiencing a Cat 5 pandemic, while other parts are seeing nothing worse than a Cat 1 or 2.
I expect we will get daily `pandemic reports', much like weather reports, tailored for each part of the globe. There may well be a lull in infections in London, while New York is seeing substantial numbers of cases.
(click to enlarge)
While there are many similarities between the hurricane and pandemic scales, there is one aspect where they differ greatly.
With Hurricanes, there are physical limitations that keep the storms from growing much stronger than 200 mph winds. Category 5 storms start at 156 MPH, and these storms are only capable of intensifying about 35% above that windspeed.
There are no such restraints on a severe pandemic. While a 2% CFR indicates a Cat 5 pandemic, so does a 10% CFR. Yet, the difference in the impact of these two CFRs would be enormous.
The pandemic scale at the top of this blog shows a Category 5 pandemic starting at a 2% CFR, and wisely shows no top limit, with the arrow simply pointed higher. A tacit admission that public health experts don't know what the upper limit might be.
Although the 1918 pandemic is often used as a model for the next severe pandemic, doctors and scientists generally admit that the Spanish Flu isn't the worst that nature could throw at us.
It was simply the worst in recent history.
Over the past 300 years there have been at least 10 pandemics. We know very little about the ones before 1900, and the lack of modern transportation likely kept some outbreaks from spreading.
The pandemic of 1781, however, is generally believed to be one of the worst in history. So any hope that 1918 was a fluke, never to be repeated, doesn't hold much water.
Another pandemic is, we are told, almost inevitable. It isn't a matter of if, it's a matter of when.
We have one great advantage over our great-grandparents who were caught by surprise in 1918. We have some advance warning that a pandemic may be looming.
Of course, that only helps if we use this time wisely and prepare.
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