Mar 09 2010
H1N1 Update
It seems as if the wave of H1N1 pandemic flu has passed, so it is a good time to get up to date on the status of the pandemic. For background, the H1N1 is a strain of influenza A that cropped up about a year ago. It was declared a pandemic by the World Health Organization (WHO) last Summer.
The pandemic spawned a number of controversies. The last H1N1 outbreak, called the “swine flu” (a bit of a misnomer) was in 1976. The vaccine for that strain caused Guillaine Barre Syndrome (GBS) in about 1 in 100,000 people vaccinated. Therefore with the roll out of the new H1N1 vaccine there were cries from the usual assortment of anti-vaccine and other cranks that the vaccine would cause GBS, even though the last 30 years of seasonal flu vaccine has not caused any such outbreaks (at worst the seasonal flu vaccine causes an extra one case of GBS per million doses, but even this is questionable).
There were also accusations that the flu pandemic was a scam created by Big Pharma to sell vaccines, and the real conspiracy nuts claimed that the vaccine was in fact designed to infect and kill people.
Meanwhile, there were questions (legitimate and nutty) about how severe the pandemic actually would be. Of course, no one could know until after it happened.So how bad was it? Here is the updated numbers from the CDC:
# CDC estimates that between 41 million and 84 million cases of 2009 H1N1 occurred between April 2009 and January 16, 2010. The mid-level in this range is about 57 million people infected with 2009 H1N1.
# CDC estimates that between about 183,000 and 378,000 H1N1-related hospitalizations occurred between April 2009 and January 16, 2010. The mid-level in this range is about 257,000 2009 H1N1-related hospitalizations.
# CDC estimates that between about 8,330 and 17,160 2009 H1N1-related deaths occurred between April 2009 and January 16, 2010. The mid-level in this range is about 11,690 2009 H1N1-related deaths
In the last 10 years the seasonal flu has killed on average 36,000 Americans. The numbers above are just for H1N1, and are on top of seasonal flu numbers (although I have not seen any final numbers on the seasonal flu yet).
So the net effect of H1N1 was to give us an especially bad flu season, but not the worst-case pandemic that was feared. It should be noted that seasonal flu kills mostly those >65 years old, while the H1N1 killed disproportionately those under 65, and also was more fatal to pregnant women. Raw numbers do not reflect this difference.
How about the GBS fears? Cases of GBS were carefully tracked by the CDC and in other countries and there was no increase in GBS associated with the H1N1 vaccine.
While cases are dwindling, the H1N1 pandemic is not quite over. It may be burning itself out, but cases are on the rise still in Africa. This leaves open the possibility that it could come back around. We have already had two waves of H1N1, and a third wave is possible. Further, it is the later waves of such pandemics which may be the most deadly. There has been a new mutation identified in a Mexican patient – and that is the concern, that the virus will mutate to a more virulent or contagious form before it comes back around. It is also possible that this strain of flu will simply combine and synchronize with the seasonal flu.
Thankfully, the H1N1 pandemic was a bit of an anti-climax. While it did bring a particularly bad flu season, it was toward the mild end of the spectrum of predictions. But also, all the fear-mongering about the flu vaccine also fizzled. The vaccine was safe and effective and served to blunt the effects of H1N1.
We will continue to track H1N1 as it may have another act to play.
Addendum:
After I posted the blog the representative from the CDC I had left a message with got back to me, just to confirm my reading of the stats.
The figures posted above are the hospitalizations and deaths from H1N1 alone, but essentially there were negligible cases of seasonal flu this year. This is still a big mystery – we were expecting H1N1 + seasonal flu, but the seasonal flu never showed.
Speculations as to why: high vaccination rates and high rates of compliance with good hygiene and people staying home if they were sick. There is also speculation about the H1N1 “crowding out” the seasonal flu strains, but this is not an established phenomenon.
The bottom line is that the flu is unpredictable – chaos theory in action. It will probably take a year or two to sort out why things happened the way they did.
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29 Responses to “H1N1 Update”
I’m just curious; given that all reports show that almost all flu seen his year is H1N1, how is one-third the normal annual deaths from flu a “particularly bad flu season”?
Also, perhaps you might explain why I knew maybe 10 people who had the swine flu over the last ten months (note that I live in New York City with two six year olds in two different public schools, and the virus started here six months before a vaccine was available), yet, in the last month, I’ve been in conversation with at least 20 to 30 people who have had the stomach virus that is going around?
Could it be that there was a massive overreaction on the part of the government, doctors, and medical professionals? Could it be that all the medical tests and research and press conferences blinded us to what was plainly visible to “average” New Yorkers in April, May and June of last year?
Sure, it’s better to be safe than sorry. But was the hysteria really worth it?
Carl Zimmer wrote about what sort of effects H1N1 might have had on prevalence of the seasonal flu a few weeks ago:
http://blogs.discovermagazine.com/loom/2010/02/16/the-ever-surprising-swine-flu/
I guess at least as of then preliminary data seemed to indicate that the seasonal flu was shaping up to be not as bad as usual. So I guess the questions will be 1) when its all said and done will 2009 H1N1 + 2009 seasonal flus equal fewer deaths and hospitalizations than average seasonal flus and, 2) if that’s so, why?
I know this is way off topic (sorry), but HuffPo is at it again, this time from Jenny McCarthy herself:
http://www.huffingtonpost.com/jenny-mccarthy/whos-afraid-of-the-truth_b_490918.html
David:
The flu season is not over yet, so you cannot compare to total numbers from previous seasons.
While total deaths are down, more people died directly from the flu rather than from complications. This is relevant because it relates to the fact that the flu itself was more severe, and it killed more young people. Lost life years is greater because the average age peaked in the 40s for H1N1 rather than >65 for seasonal flu.
I also don’t think you can argue that there was an overreaction, or that the course of the flu season was “obvious.” The H1N1 vaccine was a particularly good match, precisely because we had warning. And we can never prepare for the flu season that will come, only the range of probability of what might come. No one has a crystal ball.
It is not hysteria to prepare for a bad (not even the worst) case scenario. And don’t confuse preparedness for the media hype.
I’m just curious, but maybe David could explain how we overreacted at all? As far as I can tell – except for some standard media frenzy – all we did was develop a new vaccine and warn people to take basic hygiene precautions. No schools were closed, no public events were canceled, no travelers were quarantined.
As to mortality: 36,000 seasonal deaths is just a well-publicized guess; amalgamating all excess mortality during influenza season because influenza deaths are rarely tested or reported. This study suggests only about 6,000 can be directly attributed to influenza and pneumonia.
http://jama.ama-assn.org/cgi/reprint/289/2/179
On the other hand, pediatric influenza deaths have long been tested and reported, even for regular seasonal influenza. As of Feb. 27, 2010 256 children had died because of H1N1.
http://www.cdc.gov/flu/weekly/
During regular flu seasons, though: only 22 children had died by Feb. 28, 2009
http://www.cdc.gov/flu/weekly/weeklyarchives2008-2009/weekly08.htm
and only 24 children had died by Feb. 23, 2008
http://www.cdc.gov/flu/weekly/weeklyarchives2007-2008/weekly08.htm
Thanks for the update Steve! I have a quick question for anyone who cares to answer. Why was the H1N1 strain not included in the seasonal flu vaccine? Was it merely a matter of timing, or were there other issues with the virus itself?
@krazy9000
If you mean the 2009-10 vaccine, it’s because the H1N1 virus emerged a few weeks after the vaccine strains were finalized. The good news was they could develop a brand new H1N1 vaccine pretty quickly using the standard strain-change techniques they use every year for new seasonal vaccines (although they performed safety trials, etc for due diligence).
If you mean the 2010-11 vaccine, both the WHO has recommend and the US FDA has decided to include H1N1 in the next seasonal vaccine. That way everyone should be protected, barring any serious mutation. This vaccine would serve as a useful booster for anyone who got the H1N1 vaccine, too, I think.
The media overreacted, but I think that was summed up nicely here:
http://www.badscience.net/2010/03/when-is-it-okay-to-ignore-people-you-dont-trust/
With the comment on actuarially appropriate level of media health coverage, although I suspect the “smoking kills”/”smoking maims”/”smoking is bad for you” stories would get tedious after a while.
It is hard to tell even after event how things could have panned out if different responses were in place. I saw somewhere a conference report that the seasonal vaccine was significantly effective against AH1N1. That would also help explain immunity in older people (who usually get the seasonal flu jab), but I don’t know if that research panned out.
I have some sympathy regarding the stomach virus comments. Norovirus is horrid, and immunity is often temporary so you can get it again and again with a short break in between. Vaccines are on the horizon for norovirus, but I’m guessing initially the hospitals will snap them up to try and clear the damn thing out of hospitals. Not heard of norovirus pandemics, but maybe that is just luck. And yes the antivaccine lot are already pouring scorn on some of the norovirus vaccines, guess that shows how “religious” the argument is for some of them.
Hello Simon,
Take a look at this article written by Ben Goldacre last year.
http://www.badscience.net/2009/04/parmageddon/
I didn’t see an overreaction. In my personal life, I saw more H1N1 “skeptics” claiming that the media was overreacting than I actually saw anyone overreacting.
Encouring people to wash their hands, stay home when sick and get the vaccine when available isn’t an overreaction.
There is something about the H1N1 epidemic that’s kept bugging me. Here it goes: I’m from Sweden, and over here we had our own controversies around vaccinations and so forth much like you in the US had but somehow I swear we received more of a glancing blow than you did.
I just ran a highly unscientific comparison of the numbers and they actually seem to support this. Focusing only on fatalities and population:
US: 12K out of 300M, 0,004 % death rate.
Sweden: 24 (exact) out of 9M, 0,00027 % death rate.
That means the US would have been hit about 15 times as hard as Sweden as far as mortality is concerned.
And my question lingers: why. We’re dealing with an epidemic with a high virulence factor, geography shouldn’t explain it. Infrastructure, culture and urbanization levels are about equal.
As for vaccination: we we’re hit later and fully vaccinated the entire population (well, those willing anyway) which should count for something but not a whopping 1500 % gain in resistance.
So I’m running out of ideas here. Climate? Differing definitions of H1N1 associated fatalities in statistics? Or is it simply just not possible to make comparisons at this point and with this data?
Ideas?
-This is still a big mystery – we were expecting H1N1 + seasonal flu, but the seasonal flu never showed.-
People probably worried and did what they are always supposed to do for flu this time. Basic common sense hygiene, not turning up for work when you are sick etc…
Which would say a lot about humans. Not so much about the flu.
Does the following data exist?
# or % of poeple who got hospitalized that were immunized (or not)
#or % of people who died that were immunized (or not)
seems to me a decent case could be made for immunization if this data was available.
Child deaths, child deaths, child deaths.
IIRC, in a “normal” flu season it kills about 40 children.
Latest CDC weekly figure is 265 pediatric deaths.
A statistical blip in a nation of over 300 million, but I’m sure it mattered to their parents.
I wonder how many of the above could have been prevented if we had used those ‘evil’ adjuvants to stretch the initial limited supply of vaccine.
@ Stroh
I think for your comparison it would be better to use the 2,009 confirmed H1N1 deaths in the US rather than the 12,000 estimated deaths. This would give a .00067% mortality, which is still quite a bit higher than Sweden.
I can only guess why this would be the case, and I’m sure that even real scientists will need a lot more data before they can make any conclusion. Sometimes viruses just behave a little differently in different populations. Avian (H5N1) influenza, for example, has been about 29% fatal in Egypt but 82% fatal in Indonesia (taking Indonesia’s reported cases at face value).
Another consideration could be the ratio of ICU and ECMO units to population in Sweden. In many places in the US, hospitals were just barely treading water in keeping critical H1N1 patients alive. If more such machines were available in Sweden, it could have helped the situation.
Thanks, Mr. Novella, for the thoughtful response.
Granis, I don’t want to get into a pissing match on Mr. Novella’s blog.
However, press conferences almost every day, expensive advertising campaigns (paid for by our tax dollars), non-stop media coverage, lines for vaccines down the block, attempted mandatory vaccination that almost resulted in legal proceedings, parents freaking out on their pediatricians, conspiracy theorists talking about how the virus has mutated in Ukraine among thirty other wild theories, people in masks in the streets — all of this is not a normal reaction.
I shudder to think how the delicate modern individual would have survived 100 years ago before many of the wonders of modern medicine were discovered and developed.
@ Granis
Good point. I had a feeling there was something up with the statistics.
The remaining difference could quite likely be contributed to vaccination and general preparation, courtesy of the additional month or so we had for planning.
What is most frustrating when discussing the H1N1 “scare” is how arrogant people are. Sweden was when of those nations who, apparently, had entered an agreement with Glaxo-Kalsmith to receive the first batch of whatever vaccine would be produced for the next pandemic which in this case was H1N1.
And how does the general public thank the government for caring? By yelling at them that they are wasting our tax money, accuse them of conspiring with GK for profit and smugly conclude that since the pandemic wasn’t that bad it was clearly incompetent of the government to protect us from it. Oh, and don’t forget those scheming doctors. We all know THEY just did it for profit (hint: a doctor’s paycheck in Sweden has nothing to do with how many vaccines he gives.)
Sure, maybe 18 million doses for 9 million people was overkill. But what if this has been the new Spanish Flu? Should they have waited until people dropped dead in the streets before placing the order?
Oh, and to top it all of we swedes had our first run-in with the anti vaccination lobby too. All sorts of myths began circulating about how the vaccine could kill you, paralyze you, weaken your immune system, give you Alzheimers and god knows what. All the while “experts” featured on prime time telling us how getting the flu “is really good for us!” and how if we just ate our vegetables we would be immune anyway. Madness, I tell you.
Even though everything was done just right, it became a huge PR-loss. The risk is that next time a pandemic rolls around that is more deadly than this one people will not vaccinate themselves well enough. And we will all pay the price for that.
Oh, about ECMO: we had similar problems as the US with risks of shortages. Some patients had to be shipped to hospitals in neighboring countries for optimal treatment.
In the end, we made it through. If barely.
David in NY:
j
Short answer: they didn’t.
A century ago children died at rates that are simply frightening. Do a little family history checking and you will find great aunts and uncles who never made it past childhood. Old city cemeteries have several graves of children. I went past one and noted that four children in one family died within a month about a century ago (possibly from diphtheria).
Then don’t forget that less than a century ago millions of healthy adults died from the influenza epidemic. A couple of suggested books to read: Flu by Gina Kolata and The Great Influenza by John Barry.
By the way, this is the personal blog of Dr. Novella. Since you used “Mr.” twice, I am going to assume it was a deliberate slight, not a typo.
Dr. Novella concluded his post by saying that the HiNI vaccine was
‘effective’. Could he or someone show the evidence of effectiveness? Not being a scientist or M.D. I must have missed it in his or other posts here.
Thanks.
@oderb
Here’s a study published in the New England Journal of Medicine.
http://content.nejm.org/cgi/content/full/361/25/2405
They say,
“Results: By day 21 after the first dose, antibody titers of 1:40 or more were observed in 114 of 120 subjects (95.0%) who received the 15-µg dose and in 106 of 119 subjects (89.1%) who received the 30-µg dose. A similar result was observed after the second dose of vaccine. No deaths, serious adverse events, or adverse events of special interest were reported. Local discomfort (e.g., injection-site tenderness or pain) was reported by 56.3% of subjects, and systemic symptoms (e.g., headache) by 53.8% of subjects after each dose. Nearly all events were mild to moderate in intensity.
Conclusions: A single 15-µg dose of 2009 H1N1 vaccine was immunogenic in adults, with mild-to-moderate vaccine-associated reactions.”
“By the way, this is the personal blog of Dr. Novella. Since you used “Mr.” twice, I am going to assume it was a deliberate slight, not a typo.”
Ah, yes, the famous nasty cranks that like to monitor the comment sections of their favorite cause blogs, usually for lack of anything better to do.
It wasn’t a typo or a slight — it was a stupid mistake. I was trying to be polite, as I don’t know the man personally and wouldn’t presume to call him “Steve.”
There is no justification for slighting someone as accomplished as Dr. Novella, nor is there any justification for attacking someone who wants to question Dr. Novella.
I know we want to believe that science is infallible, but even a cursory knowledge of the last 100 years of modern medicine reveals a vast wasteland of theories that were thought to be ironclad irrefutable at the time of pronouncement.
With knowledge as limited as ours (despite major advancements in recent years), and frailties to numerous and embedded and varied to mention, there can be no black and white. Not yet, anyway.
Sorry.
the thing about pandemics is the genetic shift. genetic drift isn’t so bad since that is what causes the epidemics from time to time. But the shift is the killer. It only happens to A strains and occurs in a completely unpredictable fashion creating a virus that the human population is susceptible to.
David, do some basic research. No one has ever claimed science is infallible. If science was infallible it would stop! (there is a video on that, it involves folks like you going into a sack, I found it!)
Anyway, despite you being clueless on Dr. Novella’s credentials (did you miss the bit where he was the neurologist consulted by the TV show Inside Edition on the woman who claimed to get dystonia from a flu shot? or did you miss clicking the “about” tab?)… you seem to be negligent on the history of science. I suggest you actually read the two books I suggested before you come back and lecture us on what science should and should not do.
“I know we want to believe that science is infallible, but even a cursory knowledge of the last 100 years of modern medicine reveals a vast wasteland of theories that were thought to be ironclad irrefutable at the time of pronouncement.”
Yes David that is 100% true and the way it is suposed to be. Participants of science are constantly checking and doulbe checking each other, refuting claims, providing evidence and these are the things that steer the ship.
If you look OUTSIDE of science you find a vast wasteland of nonsense and utterly ridiculous, and demonstrably wrong “knowledge”. Just look at anything that science has peered it’s eye at, but practitioners have not. Magic crystals, meridians, dowsers, chi, this list is endless. But its doesnt change. It has become dogma.
These are things that are demonstrably wrong, demosntrably work on placebo or one human bias or another (usually confirmation bias). But yes, people who do nt bother to engage in science still think it is real.
Its further, more often than not, the scietific method provides greater accuracy, not a 180 degree turn around (although that certainly happens). Asimov has a great quote specifically about the effect you are talking about:
“[W]hen people thought the Earth was flat, they were wrong. When people thought the Earth was spherical they were wrong. But if you think that thinking the Earth is spherical is just as wrong as thinking the Earth is flat, then your view is wronger than both of them put together.”
@ david
the hysteria was really worth it.
If you look at the CDC numbers about 2 in 9 people died of swine flu. This was a slightly different strain than the 1918 spanish H1N1 (minor nucleotide mutations, etc) and the 1918 strain was much much deadlier.
but all the hype and hysteria could have evoked paranoia, which would make people simply act more conscious about covering their mouths when they sneezed or leaving an enclosed area when someone else sneezed. And of course hand washing.
Sam Pennella
2 deaths for every 9 infections is actually a little bit off. ^
Would herd immunity have had any impact in preventing the spread of the current H1N1? Part of the reason I ask I didn’t get the vaccine myself, due to bad scheduling and not anti-vax nonsense.
The other reason is a friend of mine is didn’t vaccinate his kids, and he takes particular joy in his Board of Ed’s concerned reaction. He didn’t say how he arrived at his decision, but I’m sure actual medical experts weren’t a factor (experts, whadda they know?)
[...] Antivaccine movement’s bad PR hits critical mass By Michael Rosch, on March 17, 2010, at 7:03 am Six months ago we were looking at a serious flu pandemic, a very strong and vocal campaign demonizing vaccines, as well as a growing public distrust of vaccines and the entire medical industry. But then a funny thing happened. Despite all their bark, the antivaccine movement proved to lack sufficient bite, as enough Americans still seem to have gotten vaccinated against one or both prominent strains of flu, leading to a dramatically reduced number of flu cases and flu-related deaths this season. [...]
I don’t think that influenza vaccines every achieve a very high level of herd immunity, due to the relatively low percentage of people who get their annual flu shot.
That’s not to say that vaccinating doesn’t help protect the unvaccinated. It’s just that we don’t acheive enough collective immunity to develop an impenetrable national defense against major outbreaks.