Entries in influenza (3)
The H7N9 outbreak continues to grow. This morning, both Flutrackers and Avian Flu Diary are reporting multiple Chinese stories that two new and previously unreported human H7N9 cases have been found in Hangzhou, Zhejiang Province. Both cases have died.
The machine translation from Chinese to English can be problematic where date (well, pretty much anything else) is concerned, so it takes skill to parse correct dates from the rest of the dialogue. Regrettably, that is a skill I lack. But many others do, and these talented people are all located on Flutrackers.com.
There appear to be two separate dates of infection. One apparently is the 7th of March, and the other is the 25th of March. But what is plain is that this brings a fourth province -- and third coastal province -- into the picture. By any yardstick, we have not yet defined the scope of this outbreak. Although it appears human-to-human transmission may or may not yet be possible, and as we covered at length yesterday, H7 can and does infect humans, the cat appears to be out of the bag.
The biggest impediment to getting our arms around the scope of the crisis (yes, I consider this to be a crisis, because we have a novel strain of influenza that no one, outside a random poultry worker or hunter is immune to, and it is killing people): It is not killing poultry. Sentinel chickens (the proverbial canary in a coal mine), used to help detect the presence of avian influenza, may be asymptomatic carriers of the disease. At least that is one oprevailing theory, which would also explain why and how this virus escaped surveillance and, thus, early detection.
You always knew when H5N1 bird flu was close by: You could follow the trail of dead and soon-to-be-dead chickens. H7N9 is not killing chickens. Nor, contrary to what our deepest nightmares and feelings might tell us, is it killing pigs.
My blog of yesterday mentioned a Dr. Yin of the Bill and Melinda Gates Foundation. Apparently Dr. Yin is the Foundation's leader in China. And it was quite satisfying, knowing Bill and Melinda are spending funds in China, including, but not limited to, surveillance. Dr. Yin's statement is worth paraphrasing. He said, basically, if you don't test for H7N9, you won't find it. But if you do test for it, you'll find it. The inference is that there have been numerous unexplained and undiagnosed severe respiratory ailments there this season. Retroactive testing of samples, based on Dr. Yin's inference, will yield a significant increase in the number of H7N9 human cases.
I am hopeful that the CDC here will start looking at the number of "A (subtyping not performed)" samples still lingering around.
Hello, whatever-is-left-of-my-personal-blogosphere! I know I have not blogged on disease in quite some time. For that, I plead guilty, with an explanation.
My day job -- my career as an incomparably-talented and world-renowned IT leader -- has been very demanding over the past year or so. Plus, to be honest, I think I have been suffering from "post-pandemic shutdown."
I know other bloggers have been dealing with the aftermath of the H1N1 swine flu pandemic. We all have sort of branched out to engage other diseases. But influenza is what got me into blogging, and influenza is still at the core of all disease bloggers' interest.
We are all grateful that H1N1/2009 was the relatively mild event that it was. But we also know that another pandemic always lurks around the corner, behind the building and out of view. We also know that at least one pandemic each century is a real humdinger, death-wise.
Nonetheless, like Y2K before it, the H1N1/2009 pandemic was surely viewed by the global mainstream media as a sort of nonevent. Never mind how much work we all put into preparedness. never mind how much money went into culling poultry (and compensating farmers worldwide). never mind how much Tamiflu and Relenza we stockpiled around the world. And never mind how much went into drilling exercises and preparedness messages into our citizens' heads.
So it was a great and pleasant surprise to stumble upon this trailer for the upcoming film Contagion. I am a huge film buff, and I was reading about the progress of filming the Max Brooks zombie masterpiece World War Z in Malta and Scotland when I saw a link for a trailer for some film called Contagion.
This is what we thought we would see from Hollywood back in 2006 and 2007. Instead, we got the passable but still pedestrian Bird Flu: Fatal Contact Movie of the Week. How this film's existence got by me is unknown, me being such a big EOTWAWKI (End of the World as We Know It) film kinda-guy. Especially with it being a BIRD FLU MOVIE!
The film is directed by Steven Soderberg, he of the Oceans (Clooney-Pitt) movies and Out of Sight, The Limey, Traffic, and Erin Brockovich. It stars Matt Damon, Gwyneth Paltrow, Kate Winslet, Jude Law and Lawrence Fishbourne. After watching this trailer, I think we can agree that this should be one helluva scary film. Listen closely to Fishbourne's character deliver one of the best lines in recent cinematic history. Post a comment and let me know which line I am talking about.
The Centers for Disease Control and Prevention issued an update regarding swine flu, or H1N1v, today. The numbers draw me to draw up an interesting set of suppositions. I thought it would be of importance to parse these numbers, analyze them and draw some observations and conclusions from them.
First, as everyone wants to know, just how many people in this country have died from H1N1v? Well, the CDC's answer to that would make Harry Truman cuss.
CDC Estimates of 2009 H1N1 Cases and Related Hospitalizations and Deaths from April 2009 - January 16, 2010, By Age Group
|2009 H1N1||Mid-Level Range*||Estimated Range *|
|~19 million||~13 million to ~27 million|
|18-64 years||~33 million||~24 million to ~49 million|
|65 years and older||~5 million||~4 million to ~8 million|
|Cases Total||~57 million||~41 million to ~84 million|
|0-17 years||~82,000||~58,000 to ~120,000|
|18-64 years||~150,000||~107,000 to ~221,000|
|65 years and older||~25,000||~18,000 to ~37,000|
|Hospitalizations Total||~257,000||~183,000 to ~378,000|
|0-17 years||~1,230||~880 to ~1,810|
|18-64 years||~8,980||~6,390 to ~13, 170|
|65 years and older||~1,480||~1,060 to ~2,180|
|Deaths Total||~11,690||~8,330 to ~17,160|
OK class, let's follow along. And let's just look at that last row. The CDC states that anywhere from 8,330 to 17,160 people have died in America from H1N1v or its complications. Using an algorithm to determine the midpoint (and I am certain that statisticians much, much smarter than I have alloted for the severity of the virus being greater in Wave 2 than in Wave 1), the midpoint is pegged at 11,690. That is an increase of 530 Americans since the previous report in mid-January.
Everyone wants an exact number, which of course is both meaningless and impossible to produce. But I want to stress that these are the same algotithms that produce the vaunted, take-it-to-the-bank figure the global press uses to determine seasonal flu deaths. Does this sound familiar?
"Annually, some 36,000 Americans die each year from seasonal flu."
That mantra is repeated over and over and over again. Repeated so much so, in fact, that it has become a pillar of certainty. Some recently have dared to debunk that wisdom, saying that, in fact, the number may be closer to 20,000. But it matters not. the number 36,000 is etched into the National Consciousness forever.
Good! Let's use that figure and compare apples to apples.
The CDC states that 90% of all seasonal flu deaths are persons ages 65 and older. But in this current pandemic, just over 87% of the deaths are of persons aged 64 and younger. Only 12.6% of the deaths are of persons 65 and older. A full 10.5% of the deaths are pediatric (ages 0-17).
For those who believe this H1N1v to be a "false pandemic," your argument just got shot out of your backsides. In a traditional flu season, fewer than 1% of the deaths are of children ages 0 to 17. In fact, that number is fewer than one-half of one percent. So the number of children who have died from H1N1v is seven times the yearly average. Sorry, debunkers. You don't generate those kind of numbers with seasonal flu, no matter how bad it is. Only a bona-fide pandemic generates that type of data. And that kind of death. Checkmate. Game, set and match.
Enough b**ch-slapping of the "false pandemic" crowd. Let's get back to the numbers at hand. And let's also look at what this virus might eventually do, according to Dr. John Oxford. It's a long road, just follow my logic.
Eventually, based on previous pandemic flu virus behavior, this flu virus is going to mutate. There is already some evidence of two key amino acid substitutions in the receptor binding domain, popping up in multiple areas of the planet pretty much simultaneously. (Receptor binding domain means the way the virus latches on to cells in the epithelial tract, for those of you in Rio Linda).
As influenza is wont to do, it produces thousands of mutated offspring, and one particular offspring seems to be at the very least, trying to take root in several locations all over the world. If this mutation takes hold and replaces the current H1N1 strain, it will pose a serious risk of producing additional sick and additional dead, based on the fact most of the amino acid changes were detected in the lungs of dead victims. But whether or not this mutation holds is simply speculation and we will not know it unless and until it manifests itself in numbers large enough to be detected.
What we do not know yet is what form and substance H1N1v will take to alter its proclivity toward younger hosts and start zeroing in on the elderly. But we can be assured enough to bet that once again, based on prior pandemic virus behavior, and as Sam Cooke famously sang, A Change is Gonna Come.
But wait, you ask. Just today, the WHO today released a report that said, in essence, that H1N1v is slowing down throughout most of the world. The notable exceptions are Asia, eastern Europe, and certain African nations. In Australia, the virus has almost disappeared -- and isn't that not supposed to happen with a pandemic strain?
A flu virus slows down when one or more of several things happen. the virus slows down when climate changes in a way unfavorable to the virus (high temperatures with high humidity, for example). This explains why, in Australia and Brazil, for instance, the virus is laying very low.
Another reason why the virus may slow down is that it has burned through its largest pool of available hosts. At that point, the virus has three directions it can go. It can die out, it can be overtaken by another flu strain, or it can evolve around the problem.
Most pandemic flu strains choose the latter course and evolve, or mutate, or whatever you want to call it. Publish or perish? With viruses, it is evolve or perish. This has been repeated over and over and over again too many times to count. This is how we get seasonal flu. This is why we get flu shots annually, instead of once or twice. Why in the world anyone would expect this virus to simply lay down and die without fighting is contrary to every known rule (or supposition) regarding the behavior of influenza.
So this virus, when faced with a loss of available hosts, will probably do what the overwhelming majority of pandemic and post-pandemic viruses will do: It will evolve and seek other hosts.
So we've got nearly 12,000 dead in the USA from swine flu, and only 12.6% are seasoned citizens. Now what happens when this virus changes its genetic structure and starts infecting those seniors?
We get 36,000 dead annually.
Add the potential for the addition or retention of those two amino acid changes, and we get a virus that quite possibly will evolve beyond the original vaccine target. Or maybe not. The smart play would be for anyone not yet vaccinated to hurry up and get that dang shot! And for parents of kids under 9 to get that H1N1v booster shot. Remember, ages 9 and under need two jabs.
Let's do the math. Take 12,000 dead, and add 36,000 to it. That is 48,000 people. That is more than died in the 1968 pandemic and is about the same CFR as occurred in 1968, adjusting for population. But if this virus gets any more lethal, and we could be looking at numbers comparable to the 1957 pandemic.
Quoting the the UK's Guardian, The last big flu outbreak in Britain occurred in 1999/2000, when 22,000 people died, which is 10 times the average for a winter flu season. Professor John Oxford is one of the oldest and most respected flu researchers on the planet, and is habitually quoted on this Blogsite. In late December 2009, Professor Oxford famously said (thanks to Crof for the link):
My greatest fear is that the virus will mutate next year, to enable it to infect older people. If it does, then the death rate next year will be much worse than this, perhaps even as high as the winter of 1999-2000.
Remember that between a third and a half of all people who have ended up in intensive care with swine flu were previously completely well; they weren't asthmatics or on chemotherapy. While the pandemic has been fairly mild here, I think it will kill off for ever the notion (among doctors and the public alike) around influenza that "Oh, it's only flu".