Like I wasn't going to make a post about this? =)
I don't have sage advice to offer; I'm not a trained medical professional nor do I specialize in emergency preparedness. I am not advocating panic in the least, since the strain seems to be currently able to be effectively treated in the United States with antiviral medications.
But I do have a brain, and I thought that since enough time had passed that it was good to offer some thoughts on this...
I want to analyze this outbreak from a numbers perspective. Bear with me on this. I am using data from the CDC report from 2007-2008.
Seasonal influenza in the United States is tracked by the CDC. Not all suspected cases are tested because there are simply too many. Last year, for the 2007-2008 flu season, the CDC reports the following:
225,239 specimens tested
39,827 of those specimens were positive
18% of specimens tested were positive. That's a fairly large sample size, but not the entire sample size; this is only the sample that actually underwent laboratory testing at a CDC certified viral laboratory.
We will take a tiny, tiny leap here, and assume that the number of pediatric influenza deaths the CDC reported for the 2007-2008 season is based on specimens that underwent laboratory testing.
The number of pediatric deaths from influenza for 2007-2008 is 83.
83 deaths/39,827 positive specimens=0.21% chance of death for children with seasonal flu.
Kids are fairly susceptible to the flu, but we can get a better estimate on normal mortality of the flu for EVERYONE from the CDC's statement that the epidemic threshold was exceeded using their 122 Cities Mortality system. It peaked last year at 9.1% mortality (or cause of death in the people that died during flu season), but remember, that's not based on actual laboratory testing--it's based on a survey of death certificates in those 122 cities and which ones note the cause of death as either pneumonia or influenza. Not the most reliable of methods, but it's the data we've got.
Let's assume though, that normal chance of dying from the flu isn't that much. Other pages on the CDC site state that about 16 million people each year are diagnosed with influenza-like illness (not verified all the time by lab tests), and of those, using our fun mortality systems, we get that approximately 36,000 die each year.
Rough, rough chance of dying from the flu then is 36,000 deaths/16 million cases=0.225% overall. Remember that number, since we're going to come back to it shortly. Please note that it's statistically not that far off the pediatric mortality rate for last year, which we calculated at 0.21%.
Now let's hop over to our neighbor to the south, Mexico, which has a large number of suspected cases and some number of confirmed cases. We're not going to even bother with "suspected" cases here, we're going to use the numbers that have actually undergone laboratory analysis, according to the World Health Organization. See the NY Times article here for more information about this set of numbers.
In Mexico, they tested 908 cases for swine flu.
Of those 908 cases, only 397 cases turned out to have the particular influenza A H1N1 variant we're calling swine flu.
397 positive specimens/908 specimens tested=43.72% infection rate
Please compare that number to our regular seasonal flu infection rate of 18%.
On top of that, we also get the numbers that there have been 16 deaths out of those 397 specimens.
16 deaths/397 positive specimens=4.03% mortality rate in Mexico
Now, granted, we're dealing with a much smaller sample size than the total number of cases that were tested in the USA for the 2007-2008 seasonal influenza season. The mortality rate is likely to go way down, if they test more cases and figure the deaths against that.
We also have to take into account that Mexico doesn't really have a great infrastructure, and many of those deaths may have gone undiagnosed initially. So the medical care isn't as good there, compared to other places.
BUT... and this is the big "but" in all of this analysis.
Right now, it appears that swine flu is spreading like regular seasonal influenza. It's got a higher infection rate, but that's also based off of a smaller sample size. Statistics are hugely important here. Let's say for the sake of argument, that eventually the swine flu infection rate is found to be 18%. Common infection rate as we've established. And let's say also, that the swine flu mortality rate in Mexico is strongly influenced by their lack of medical care in certain areas of the country. Let's say, that if we didn't know about swine flu at all, and it developed in the US first, that it might have a 1% mortality rate given our much, much better medical care system infrastructure. So far we have no deaths, but that doesn't mean that there won't be deaths in the US and people are currently being uber-vigilant about any influeza symptoms.
16 million cases of influenza a year in the US x 1% mortality rate=160,000 deaths from swine flu, as opposed to the standard 36,000 deaths each season. In fact, if we're extra conservative, we can even say that maybe the US mortality rate will only go to 0.5%, which would mean 80,000 deaths instead of 36,000 deaths.
I'd like to point out that 80,000 is still a much larger number than 36,000. Those are still lives that can be potentially lost. Which is pretty much why the health authorities are ever-so-slightly concerned about swine flu....
.... because of the last thing, that might happen, which they always worry for.
Flu viruses mutate as they pass from person to person. In some seasonal flu years, the viruses undergo more mutations, and that's why a flu year may be worse than normal. The mutations do a variety of things, including change how well the body's cells can defend themselves against the virus (the 1918 flu pandemic had a doozy of a mutation), and how easily communicable the strain of the virus is.
So far, no mutations. Which is a good thing. =)
But if there were to be mutations, they could do a lot of unexpected things to the strain of swine flu virus. Not all of them good. Most of them bad. Including, as mentioned above, making the virus affect people with better immune systems (thus causing cytokine storms like in 1918) or it could make the virus pass from person to person more easily or it could just make it stick around in our bodies longer and be a bitch to cure.
We don't know what will happen--this may be nothing now, and then come back to hit us next year. It could be nothing forever. It could stay dormant in the flu virus strains for years, and then come back thirty years from now, as is the nature of diseases.
So it's nothing to worry about now--not unless there are mutations to the virus strain or we start having more deaths in the United States or the antiviral medications stop helping alleviate the symptoms. It's not a cause for panic, but I think it is necessary for you to understand the math behind it all, and to make your own informed decisions.
A 0.225% mortality rate isn't much. A 1% mortality rate still isn't great. The 1918 flu pandemic had a 2.5% mortality rate, when all was said and done, with the majority of those deaths being young healthy adults because of the mutation that caused the cytokine storms. And so I look at that 4.03% mortality rate in Mexico and I wonder... =)
Feel free to weigh in with your own thoughts.