It added that there are other conditions, such as malnutrition/overweight, which can affect the incubation and growth stages of the virus. (If you follow the link for the WHO statement, you’ll see that the agency actually uses the term “very rare.”) It’s important, though, to understand that “very rare” is not a standard phrase either when talking about outbreaks (and it doesn’t appear to be as useful to epidemiologists), because a very large number of cases are actually “close” to rare. This chart from the CDC, obtained by Reuters , takes this in turn:
So the rate of “close” to rare is low. And it has been below “close” to rare for quite a while. And it’s true that the virus has spread more rapidly in China, Taiwan, and South Korea, three of the countries most affected. But it appears that in the most recent outbreak , it has actually been spread more rapidly to neighboring countries. And that appears to be the case, too.
The CDC’s claim that the virus has “spread more rapidly throughout the world” seems to be at odds with this chart:
And what constitutes a “large number of confirmed, probable, and suspected cases?” That depends on your definition of “large number.” Here, the CDC’s own numbers exclude cases found in the U.S.:
I reached out to Reuters to get a better idea of why these numbers are the way they are (for a start, these numbers are only for the U.S. and China, since there are many other countries in which at least some cases turned out not to be “confirmed,” although the numbers might be too low or high for some countries), but have yet to hear back. But you can get an idea from this discussion on Reddit , which raises another question about this chart: what percentage of people who become infected were found to have had contact with other ill people as well? That’s a very interesting question, which many people, particularly health care workers, might be wondering. So let’s look at that:
This chart is from an article by Michael Klare called “The Health Care Worker’s Dilemma” (which is good reading). To understand it: it compares the number of sick people who went to a health centre or clinic as defined by the WHO and were admitted during a given period. But in this graph above, the sick people are the blue dots in the upper left-hand box and are the ones who can then be shown on a map. So people in the northern part of the map have fewer of these patients than people in the southern part of the country, who have fewer of these patients than people in the central part (but the map is still pretty much rectangular, so I am not sure how to interpret it here). I suppose that the people in the middle are those who go to a health centre but have not yet been admitted. They’re all the people in the lower-right corner: the people who had only a suspicion or a partial suspicion of the infection and had some contact with them. (But they’re not all the people with positive test results, since many people don’t have a test result at all.) (If you have the CDC’s figures, the number of visits to these emergency departments on average per person in the United States is approximately 100 per year, so at 100 visits per person (I think it’s closer to 100 than 100.5), we’d have a total of roughly 400 visits per year.
There is no doubt in my mind why the CDC’s claims this week to have had 3 million cases of Ebola in West Africa are so scary. We were not, as they say, spared by this virus that had no known vaccine, no known treatment, and can spread from person to person in just seconds. These are facts; they are not “unexpected” or “unseen.” And the facts are that people are going to die of this, because in the case of outbreaks like this, it is much easier to put an infection into a place and then move onto the next infected person than it is to treat and cure a person with a preventable infection. As usual, we don’t even have a complete list of how many people have died of the outbreak, we only know that there were 3 million cases. So while the CDC’s claims are true, these are mostly just “facts,” and are not necessarily facts that we should celebrate.