Sep 09 2009

H1N1 Flu Is Still a Threat

As the H1N1 flu pandemic of 2009 continues we are slowly learning more and more about it. The challenge is that health organizations and governments are trying to optimize their response to this flu strain in the midst of the pandemic unfolding. It’s like preparing for a hurricane as it’s happening, without knowing where it will make landfall, how strong it will be, how much water it will drop, and if the levies will hold. The best option is to prepare for the worst while hoping for the best.

There are two key features of flu strains that we track – infectiousness (how easily it spreads) and virulence (how severe an infection it causes, and specifically what is the percentage of hospitalizations and deaths). What we can say at this time about the current H1N1 strain is that it is about as infectious and virulent as the regular flu-season flu. This may make it seem like not such a big deal, but of course the regular flu season kills 36,000 people in the US alone, and about 400,000 world wide.

But as the pandemic unfolds we are learning some more details. Most flu deaths in regular flu seasons are among the elderly or in susceptible populations due to a chronic illness. The current H1N1 flu, however, disproportionately kills pregnant women and young children. Another pattern is also emerging – while in most people this strain causes a mild flu, in about 1% it results in a very severe flu with a 50% mortality rate. The severe cases develop a form of ARDS (acute respiratory distress syndrome) that destroys the alveoli (air sacs) in the lungs.

We cannot yet predict who will get the deadly form of the virus. It may be linked to genetic differences in the immune system, it may be anatomical, or it may just be bad luck – if the virus sets up an infection in the alveoli. If we could predict, that would enable us to give those who are susceptible and their families high priority in getting the vaccine.

The emergence of this severe response in 1% of the population is a cause for concern, not only because half of these people die, but because they are all severely sick and require hospitalization and even intensive care. If this pattern holds up, hospitals could be overwhelmed this flu season by young people needing ventilation.

All of this highlights the need for optimal use of the flu vaccine, and further highlights the danger of the absurd fearmongering that has been going on. The anti-vaccine and conspiracy crowds have been working overtime spreading misinformation about the H1N1 vaccine. Harriet Hall does an excellent job of taking down many of the false claims point by point. I have already written about the misinformation about GBS and the flu vaccine. And Joseph Albietz has written an excellent Influenza primer.

Unfortunately, it is easier to cause fear than to reassure with facts.

The bottom line is this: the H1N1 flu vaccine is likely to be reasonably safe and effective. While it is being fast tracked, it is using tried and true flu vaccine technology, and it is being actively studied in thousands of people. Further, the role out of the vaccine will be tracked to pick up any adverse effects as quickly as possible. Concerns about GBS are overblown, and we are likely to see the usual excess cases due to the vaccine of 1 in a million vaccinated.

The risks of the vaccine are small. Meanwhile the risks of the flu are significant – even if it remains just as virulent as it currently is. And, of course, the strain may become more virulent as it evolves throughout the flu season. The benefits of the vaccine outweigh the risks by orders of magnitude, but human psychology is not built to think rationally about such fears.

Anti-vaccine misinformation will have a real body count this flu season. That is a number we should track as well, so at least, maybe, we will learn something.

Share

30 responses so far

30 Responses to “H1N1 Flu Is Still a Threat”

  1. JFlavon 09 Sep 2009 at 9:18 am

    Would having universal health care make it easier to monitor the spread of disease?

    My thinking is that if more people had cheaply available health care, more would go to doctors and have their diseases reported. With this extra data, it might be easier to track outbreaks and movement of a disease.

    Is there any evidence from countries that do have universal coverage that this happens?

  2. Steven Novellaon 09 Sep 2009 at 9:53 am

    Yes – small socialist countries, like Sweden, have excellent health databases. Actually, the biggest problem in the US is our size, and most health care is regulated at the state level.

    But, nationalized health care is not necessary to have an electronic medical database. Either way, the same infrastructure needs to be put into place.

  3. Hubbubon 09 Sep 2009 at 9:57 am

    Steve,
    Is it possible or probable that the H1N1 could get a big enough foothold that it becomes a second recurring flu season?

    If so and such a situation were to arise, then could annual flu deaths/hospitalizations be at sustained higher levels in the coming years?

    Keep up the improvement of the public understanding of science and see you at NECSS.

  4. kvsherryon 09 Sep 2009 at 11:43 am

    I have noticed that the majority of cases that end up needing vent management in the ICU have been overweight. Do you think that this could be a possible link to the seriousness of the case and patients BMI?

  5. JeffGon 09 Sep 2009 at 1:30 pm

    I heard a new fear tactic about vaccines today that I’ve never heard you mention, Steve. A lady I work with was under the impression that once you start taking flu vaccines that your body somehow becomes dependent on them so that you’re forced into taking them from year to year. Have you come across this before?

  6. weingon 09 Sep 2009 at 3:54 pm

    Jeff,
    I’ve had a few patients give me that line over the past couple years. I have no idea who comes up with this nonsense.

  7. Zelockaon 09 Sep 2009 at 4:01 pm

    I support my local viruses by staying away from flu shots. There is no reason to get a vaccine unless you’re in a risk group. If you’re not then let your body’s immune system do its job and get a work out. Its insane how many people run around getting vaccines and antibiotics for diseases that are a minor inconvenience at best.

  8. weingon 09 Sep 2009 at 4:48 pm

    Zelocka,

    You are partially correct. However, the flu is not a minor inconvenience. Hope you don’t find out the hard way.

  9. Adam_Yon 09 Sep 2009 at 5:10 pm

    Ummmm…. My dad wasn’t in the risk group for the flu. My dad was almost hospitalized from complications from the flu. That really isn’t anything I would call a minor inconvience.

  10. Calli Arcaleon 09 Sep 2009 at 5:31 pm

    Its insane how many people run around getting vaccines and antibiotics for diseases that are a minor inconvenience at best.

    Your are correct that influenza is a minor inconvenience at best.

    At worst, it’s lethal.

    I’m getting vaccinated as soon as I can.

  11. Zelockaon 09 Sep 2009 at 6:20 pm

    Feel free. I would just rather leave vaccinations for people with a much higher chance of death then I have. I am not saying deny flu shots or get rid of them but just that you should not run around and panic unless you have risk factors. Also to point out the flu shot you generally get each year is simply the best guess at what will be the dominate flu for that year and not a golden ticket anyway.

    For HIV I would get a vaccination, for polio hell yes its vaccination time, for the flu (Especially for swine flu since that less lethal then regular flu) my body can deal with it until I get a risk factor.

  12. shoshidgeon 09 Sep 2009 at 8:06 pm

    Zelocka, the trouble is that while you may not have risk factors, the people who you sneeze on might.
    We may not be able to vaccinate everybody, but we should all keep in mind that the point of it all is to develop herd immunity, which necessitates a less self-centered attitude focused on personal risk.

  13. dwayneon 09 Sep 2009 at 8:49 pm

    I am not a doctor, Zelocka, but if the available vaccine is finite, then I agree that first priority should go to the highest risk groups.

    But:

    1. Getting a flu shot is not the same as “panicking.”

    2. If you get the flu, it is not confined to you.You potentially spread it to others who are more at risk. That’s the point of herd immunity.

    Assuming there is an abundance of vaccine, it’s best for it to be used.

  14. tmac57on 09 Sep 2009 at 10:10 pm

    Zelocka-”Especially for swine flu since that less lethal then regular flu”
    Did you miss Dr Novella’s statement that “What we can say at this time about the current H1N1 strain is that it is about as infectious and virulent as the regular flu-season flu.”

  15. baubleton 10 Sep 2009 at 12:03 am

    Dr. Novella,

    How would you respond to this Slashdot thread?

    To sum it up, many posters seems to be arguing that the dangers of H1N1 are more imagined than real, a creation of our collective, media-engorged minds.

    I am no medical doctor, but this (and the evidence they cite) is unsurprising if true. However, I read that before reading your post, so I am unsure what to think.

    It seems the data is still pending, but I know the school at which I work currently has all kinds of procedures and plans for the dreaded H1N1 outbreak.

    To be honest, my first instinct is to be skeptical of doom and gloom: bullshit.

    (p.s. Speaking of Bullshit!, I had no idea you were on the show. Your appearance on the ghost busters episode just came on the video I’m watching while I write! Proof of paranormal activity?!)

  16. BenAlberton 10 Sep 2009 at 12:53 am

    Zelocka,

    I note your willingness to be vaccinated against HIV but not Influenza and that you base that on your risk factors. I don’t know your situation, but the risk of contracting and dying from Influenza for most people would outweigh the risk of contracting and dying from HIV. Unless you have a high risk lifestyle e.g IV drug use or Homosexual man having unsafe sex or are a sex worker, the actual risk of getting HIV is very low. (Obviously this may be different if you are living in Subsaharan Africa). My point is it seems that you are not weighing risks in the way you say you are and are instead fearing HIV because in your mind it is serious and not fearing flu because in your mind it is not serious.

    I am a doctor so at some risk of HIV from needlestick injury and major Influenza risk from patient contact (though my risk of dying is small, the inconvenience is major and I would have the potential to spread it to children in my care) I would therefore take vaccinations for both.

  17. Steven Novellaon 10 Sep 2009 at 7:38 am

    The key point is that if you come into contact with someone who is high risk, or themselves is in contact with someone who is high risk, then getting the flu vaccine can prevent hospitalizations and even death.

    It strikes me as selfish, unless you are going to isolate yourself, to say there is insufficient benefit from the vaccine unless you are personally high risk.

    But it definitely is true that high risk populations and their caregivers are given priority for the vaccine.

  18. Ashon 10 Sep 2009 at 10:39 am

    Assuming that because you have no risk factors the flu won’t be a big deal isn’t really a good idea. The latest (Canadian) stats I’ve seen indicated that 2/3 of hospitalized patients did not have a significant underlying medical condition, and the median age of hospitalized patients has been around 40. The most recent local death from 2009 H1N1 was a 41 year-old marathon runner. While the chance of getting the more severe form is relatively low, an absence of risk factors is not an assurance of safety. Not to mention even a normal case of influenza is pretty nasty, and if a lot of people get it the economic costs will be significant (lost work days, businesses unable to function, etc.).

  19. Zelockaon 10 Sep 2009 at 11:59 am

    Oh caused a ruckus so let me respond in series

    Shoshidge – I never said I would not isolate myself. That is part of the societal contract we live under. And once again, the “flu vaccination” is only a vaccination for what is considered to be the most likely flu strain to hit that year. It’s not a silver bullet and I would guess that a lot of flu gets spread around with the mindset of “it can’t be flu because I got vaccinated”. It would be stupid for anyone vaccinated or not to run around when sick thinking that everything is ok.

    Dwayne – Its panicking when you have a situation like earlier this ear when perfectly healthy people are mobbing doctor’s offices to demand flu shots that are in short supply. If you have enough for everyone then that’s fine but frankly it would be of more use to set up a better control on at risk people getting the shot then just doing it come if you feel like it like we do in the US.

    tmac57 – I read the theories going back to the start of the outbreak but we now have figures on its lethality (pretty good sample size too at this point) and yes its less lethal then normal flu tends to be. It just got a lot more coverage so people are more aware of it.

    Baublet- flu itself is a pretty good killer in general of old and youth so it’s always better to have a plan but really in this world its public schools that are the major spread centers of viruses and they need a lot more tightening up in the area.

    BenAlbert – HIV and polio are both low risk to get but very high lethality. Also in both cases there are not a couple of strains of both every year to deal with so pretty much one vaccine would do you. Flu is high spread but low risk and as you said it yourself a major inconvenience for most. I believe in general biological terms that if you don’t use it you lose it so I have no problem dealing with an inconvenience to exercise my immune system at a point when I am very healthy in a completely unproven hope that my immune system will grow leaner and meaner in my later years when I need it

    Steven Novell – as pointed out anyone that gets sick should isolate themselves as much as possible anyway but, as you said and the main point of most of the arguments I see, is that healthy people should get the flu shots because non healthy people are not. Flu shots are a resource that should be better spent on risk groups and delivery too such groups.

    In general, we spend way too much time on the US trying to get flu shots to people that want them and not making sure they get pressed on people that need them.

  20. medmonkeyon 10 Sep 2009 at 2:25 pm

    There’s only one strain of HIV? That’s certainly news to me since it’s one of the most highly mutating viruses we’ve ever tried to develop a vaccine for.

  21. stompsfrogson 10 Sep 2009 at 2:36 pm

    Z-

    You can’t “run around” when you have flu.

    -N

  22. Zelockaon 10 Sep 2009 at 3:09 pm

    I only personally know of two HIV strains but then I have not spent a lot of time researching it. Either way its an example picked more for its lethality then its none shifting nature.

    Stompfang – I guess your taking that literally? I sure you likely could though I never tried it. I was using it as short hand for being mobile to different public locations and with cars that is extremely easy to do at most all stages.

  23. eiskrystalon 11 Sep 2009 at 8:57 am

    -If you’re not then let your body’s immune system do its job and get a work out-

    A warm up before a workout though is a good idea wouldn’t you say?

  24. HHCon 12 Sep 2009 at 12:17 am

    Well, I had the swine flu shot in 1976 and it made me feverish right before a statistics exam. Needless to say unless physicians are giving it away, I’m not interested in taking more shots for this year’s variation. In my readings, I’ve come across an article that states the 1918 pandemic caused millions to die worldwide, though most people who became ill did recover. It states that for the period, records were kept of those who received spinal adjustments regularly. Regular spinal adjustments were credited for a 30% increase in survival rates.

  25. son 12 Sep 2009 at 8:30 am

    Steven, Sweden is NOT a socialist country…

    it is a constitutional monarchy were both left and rightwing political parties adhere to the notion of the welfare state. Which is common in Europe.

    The current government is a center-right coalition of the Moderate party(moderate right encompassing capitalist hardliners to welfare adherents), Center party (ecofriendly center-right), Liberal party (sort of “compassionate right” in favour of the welfare state, classicaly european), and Christian Democrat party (from antiabortion, antigay to welfare adherents).

    Historically Sweden has for many years been run by the Social Democrat party (which encompass leftwing to center pro-industry and labour unions).

    Review of the “strong state” ideal here: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1328820

  26. trrllon 13 Sep 2009 at 6:48 pm

    I believe in general biological terms that if you don’t use it you lose it so I have no problem dealing with an inconvenience to exercise my immune system at a point when I am very healthy in a completely unproven hope that my immune system will grow leaner and meaner in my later years when I need it

    Exercise normally means a workout in a safe environment, not a life-or-death struggle. And make no mistake about it, an infection with influenza is a fight for your life, even if it is one that most people win. The safe way to exercise your immune system is by vaccination, giving your immune system experience in dealing with multiple influenza antigens without the risk posed by infection, and without having to depend upon chance for your “exercise.”

    I suspect that people who regard influenza as a mere inconvenience have never actually experienced it. Many people are prone to call any kind of cold the “flu.”

    And once again, the “flu vaccination” is only a vaccination for what is considered to be the most likely flu strain to hit that year.

    For seasonal flu vaccine that is certainly true, although if you really believe that your immune system benefits from regular “exercise,” I’m not sure why that should be a concern. Of course, for the H1N1 vaccine there is no guessing involved–it is already pandemic.

    I’m sure that you would not knowingly expose others to an infection that you know to be influenza. But the early symptoms of influenza can sometimes be mistaken for a cold. It would be a shame to be the vector that passes on the flu infection that kills somebody.

    I’ll be getting my seasonal flu vaccination tomorrow, and H1N1 when it becomes available.

  27. tmac57on 14 Sep 2009 at 9:25 am

    Well said trrll. Thank you.

  28. Zelockaon 14 Sep 2009 at 11:49 am

    Trrll
    Mortality rate for general flu is about .12% (worldwide all risk and age groups) That’s not enough for me to worry about at all and sure as hell not playing with a loaded gun in any way. For most the flu is nothing more than a mere inconvenience. Just because some people get hospitalized and some have a bad cold for a week doesn’t change the fact that both are flu.

    H1N1 does seem to be on the pickup though
    In case you’re actually interested in H1N1 here is a good website I found for current case and mortality rates.

    http://www.flucount.org/

    USA is in the middle of the Mortality rates currently with 2 deaths per 1 million population and a death rate that’s hit 1% (once again all age rages and risk groups).

    As for your “your killing everyone high risk around you” argument, I am pretty sure they can get the vaccination and indeed should be getting it first before all the people that would be “majorly inconvenienced” by it.

  29. trrllon 14 Sep 2009 at 2:20 pm

    For most the flu is nothing more than a mere inconvenience. Just because some people get hospitalized and some have a bad cold for a week doesn’t change the fact that both are flu.

    I still find it difficult to believe that anybody who has actually had the flu would think of it as nothing more than a “bad cold.” I’ve had bad colds, and I’ve had the flu, and they are very different beasts.

    As for your “your killing everyone high risk around you” argument, I am pretty sure they can get the vaccination and indeed should be getting it first before all the people that would be “majorly inconvenienced” by it.

    Well, I guess it must be a great comfort to have the attitude that if somebody catches the flu from you (because you are shedding the virus, but haven’t yet realized that you are ill) and dies, it is their fault for not getting vaccinated, even if you might have saved their life by getting vaccinated yourself. I suppose this also applies to people who miss getting vaccinated because they are allergic to eggs, or have another illness, and to small children who haven’t been vaccinated because they have parents who buy into the exaggerated vaccine fears being pitched on the media, or who erroneously believe that the flu is just a “bad cold”?

  30. Zelockaon 14 Sep 2009 at 3:10 pm

    Most flu cases are nothing more than a more severe version of cold symptoms. It doesn’t really matter how you think of them (or if you had a bad experience) because that’s what the data is. I have had it twice that I know of but it’s not high on my list of unpleasant diseases. Streptococcal pharyngitis comes to my mind as one of the worst (experience wise) that I actually had diagnosed.

    Appeals to emotion won’t work with me. If someone gets sick they either A: didn’t have the option of getting the vaccine (likely because a bunch of people that didn’t really need it where demanding it as par for the course in the US) or B: because they decided they didn’t want to. If A that’s a problem that needs to be addressed either by better planning of health originations or by better triage of people that do get the vaccine. If B that is there personal decision and it’s no business of mine anymore then if someone else gave me the flu and I died from it.

Trackback URI | Comments RSS

Leave a Reply

You must be logged in to post a comment.