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Flu and You (and the Vaccine)

November 1, 2009

The H1N1 vaccine is here, and after wide-spread media panic, the government trying to get as many vaccines out as possible, and plenty of anti-vaccine rhetoric flying back and forth, people are getting a bit anxious about it. For some of my friends, I’m the only one with even a superficial knowledge of medicine (I’m a biochemist and immunologist, not a doctor), so I suppose it’s natural that I’ve had a couple people call or e-mail me about what I think of the vaccine and whether or not they should get it. I’ve also seen a few people post links on facebook that I’ve tried to respond to, but I thought I should give a more thorough account here.

First, let me state my position without equivocation: Get vaccinated! I already got my seasonal flu shot, and as soon as the H1N1 “swine flu” vaccine becomes available, I’ll get that one too.

Getting the flu sucks, and vaccines are effective. They are the reason we have nearly eradicated small-pox and polio from the face of the earth. Flu is a bit different – it’s highly mutable and getting immunity one year does not protect you every year (more on that later). So why are people against vaccines? There are several reasons that I have run into, and I will try to address them each in turn.
Objection 1) Vaccines are not effective:
A great example of this is an article a friend linked to in The Atlantic. This is probably one of the most credible sources I have ever read regarding the flu vaccine (and please note that it says nothing about the safety of vaccines), but it’s still ambiguous. These are the claims article makes that I can identify:

a) Research about the effectiveness of the flu vaccine directly preventing deaths in the most vulnerable populations (the very young and the very old) is not as solid as is seems.

Yet some top flu researchers are deeply skeptical of both flu vaccines and antivirals. Like the engineers who warned for years about the levees of New Orleans, these experts caution that our defenses may be flawed, and quite possibly useless against a truly lethal flu. And that unless we are willing to ask fundamental questions about the science behind flu vaccines and antiviral drugs, we could find ourselves, in a bad epidemic, as helpless as the citizens of New Orleans during Hurricane Katrina.

There have been thousands of studies pointing to the efficacy of vaccines in general, and probably hundreds about the flu vaccine in particular. This article points to a few recent “meta-studies” that suggest that previous attempts to gauge the effectiveness of the flu vaccine may have misinterpreted the data. Essentially, they allege that the observed reduction in deaths among the elderly between those who received the vaccine and those that did not are more attributable to the differences between people likely to get the vaccine and those who aren’t (ie. poor people are less likely to get the vaccine, and poor people are more likely to die from influenza, which will skew the numbers in favor of those that received the vaccine).

There are plenty of scientists who disagree with this data, but this kind of debate is healthy in science, and I’m convinced that after a few arguments and counter-arguments have been made, we will land on a consensus that is closer to the truth. But let’s assume for the moment that the article is correct and current studies about the direct prevention of death in the elderly by the flu vaccine are completely wrong and the flu vaccine is not effective. In this circumstance, it’s even more important for people my age to get the vaccine. We know that vaccines work (see: polio, measles, small pox etc), and we know that the flu vaccine works, at least in young, healthy individuals. So it’s even more important that I don’t get sick, so that I don’t pass on the illness to someone’s grandmother. Put differently, I’m contributing to herd immunity. Furthermore, this year’s swine flu pandemic is not limiting itself to killing the very young and very old, it’s disproportionally killing people ages 25-49.

b) Placebo-controlled studies would be useful in determining the actual efficacy of the vaccines.
I’m sure this is completely true, and I would support it, but I’m a bit more callous than most doctors regarding research on people, and if you believe the vaccine is effective, it is unethical to withhold the vaccine from people that you think would be helped by it. Still, in the absence of placebo-controlled studies, one can still imagine taking an epidemiological approach taking into account socioeconomic differences mentioned above to get a clearer, less biased picture. In any case, I agree fully with this premise, but it still doesn’t argue against getting the vaccine.

c) Anti-viral medications are not as effective as they claim to be, and leads to drug-resistance.
If this is true (and it’s generally accepted that at least the second part is), then again it’s even more important to get as many people vaccinated as possible. If we can’t treat flu, then the only thing we can do is prevent it, and the single most effective way to prevent a viral infection is with a vaccine.

All in all, the main thrust of this article is that our current strategies against the flu may not be as effective as we believe, but there’s nothing there to suggest that vaccines are not the answer. Maybe we need a better way to make vaccines, so that we can make them more rapidly and not simply attempt to predict the dominant strains a year in advance. Maybe we need a better way to administer them or a way to target epitopes of the virus that don’t change as much. I agree with all of these sentiments, but I don’t think there’s any evidence here that vaccines are not the best strategy to protect people against the flu.

Objection 2) Vaccines are dangerous
I should point out up front that this claim is patently false, and I will attempt to address the main concerns that people tend to point to. The only people that are in legitimate danger from the flu vaccine are people with egg allergies (the vaccine is manufactured in chicken eggs, and the immune system is burly enough that even trace amounts of egg proteins can cause severe reactions).

First, the most easily addressed, the fallacy of post hoc, ergo propter hoc. “There was this person that got a vaccine, and then a week later she got ‘x.'” A perfect example of this is an amazingly irresponsible story from some local news program.

Doctors say that she has a rare, one in a million neurological disorder that was triggered 10 days after getting a seasonal flu shot

The story is heartbreaking, but you’ll notice that no one draws any causal connection between the vaccine and the neurological condition. The sentence above might as well have read “Doctors say she got hit by a car 10 days after getting a seasonal flu shot.” Sometimes bad things happen to perfectly good people, and occasionally those bad things will follow within days or even hours of getting a flu vaccine. If it’s something medical, like a heart attack or a neurological condition, anti-vaccination people will point to it and say: “See, the vaccine is dangerous!” even though no one can point to any link, other than a temporal one, between the vaccine and the disease. For another great example, see the story of Natalie Morton, a 14 year old girl that died tragically less than 2 hours after receiving the vaccine for HPV. News outlets flipped out and started reporting that the vaccine had caused her death, only to find out after the autopsy that she had an undiagnosed cancer that had infiltrated her heart and lungs. Let me reiterate, countless studies have been done on the flu vaccine, and the only serious risks associated with the vaccine occur at rates significantly below you general risk for contracting and dying from the flu or flu-related complications.

Probably the most common objection is the toxins contained in vaccines, notably mercury, that people will claim causes autism in children and all kinds of other problems. While it’s true that some vaccines still contain a preservative called thimerosal which has mercury complexed with it, study after study after study has shown that the amount of mercury is well below toxic levels (you’ll get more mercury if you go out for sushi). For a longer (if that’s possible) and better written description of the autism question, check out this article in wired magazine.

Twelve epidemiological studies have found no data that links the MMR (measles/mumps/rubella) vaccine to autism; six studies have found no trace of an association between thimerosal (a preservative containing ethylmercury that has largely been removed from vaccines since 20011) and autism, and three other studies have found no indication that thimerosal causes even subtle neurological problems.

So, the TLDR version: GET THE VACCINE!! (unless you’re allergic to eggs). It’s not a panacea, even if everyone got the flu vaccine every year, we wouldn’t eradicate flu. There are limitations, to be sure, but the simple fact is that it works. And it’s SAFE, at least as safe as any medication you would be prescribed by your doctor. You will not get lead poisoning, you will not get autism, you will not get hit by a car (at least, not as a result of getting the vaccine, unless you get hit by lead car on your way to the clinic to get your shot). So ignore the fear-mongering, listen to the science, and go roll up your sleeve.


Misinformation abounds on the internet, but there are plenty of sites where you can get credible, science-based information on vaccines.
– The CDC has tons of links about the supposed controversies.
– For information about all things flu-related, check out the flu-wiki
– And for a more irreverent take on this and many other pseudo-science “controversies” check out  quackcast and the millenium project.

11 Comments leave one →
  1. November 3, 2009 2:58 pm

    I really need to ask for more details if you don’t mind, Kevin…

    I was always under the impression (perhaps it’s incorrect?) that vaccines are weakened viruses.

    If this is true, isn’t there always a chance that even a weakened virus could be strong enough to beat the host’s immune system?

  2. November 3, 2009 2:59 pm

    Ohh… just thought of another question too!

    How is H1N1 a “swine flu” if humans have had it before (namely, the older generations)?

  3. kevbonham permalink*
    November 3, 2009 3:49 pm

    There are many types of vaccines, and actually the flu vaccine comes in two varieties. The kind you get with a needle-stick is killed virus – it absolutely cannot cause disease. At worst you might get a slight fever due to the acute phase response of your immune system. The nasal spray variety developed in the last few years uses a live attenuated virus that causes a low-grade infection (it’s attenuated so that it only grows at lower temperatures, so it only grows in the upper respiratory tract). So far, there have not been any reported cases of the virus reverting to a more pathogenic variety, though it is formally possible (there were a couple cases of this reported, but the ones that were tested turned out to be from secondary infections with a different strain than the one they were vaccinated with).

    As for your second question, to give a full account, it might take another post (maybe I’ll write it after my PQE), but I’ll try to give a superficial answer. Most strains of flu only infect humans, or only infect birds, or only infect pigs, but they can have similar major antigens (H = hemaggulatinin, N = neuraminidase). Without going into too much detail, the particular strain of H1N1 that is troublesome this season (that we call swine flue) has been evolving exclusively in pigs for quite some time, so there aren’t many humans that have immunity to it.

    There’s actually a different strain of H1N1 circulating this season that has not been evolving in pigs, and so some people do have immunity to it, and it’s not really causing any problems.

  4. November 3, 2009 4:46 pm

    So the H1N1 that I’ve heard through the media as being a virus humans have had before (thus it’s prevalence in younger generations, or so they say) is both kinda true and very false?

    Meaning… there is a Hemagglutinin-1-Neuraminidase-1 (H1N1) virus which humans have had before in circulation at the moment, but it’s not the one causing all the problems?

    Do both of the viruses have the same physical interactions with the body? According to Wikipedia, is related to the agglutination (or clumping) of blood cells, so do the viruses cause too much agglutination or too little?

    • kevbonham permalink*
      November 3, 2009 5:34 pm

      I think the prevailing theory is that the “Swine flu” H1N1 was transfered into pigs from humans many decades ago, and has been evolving separately from the H1N1 that remained in humans. Now that it’s popped back into humans, only people that were alive back when the transition was made have any immunity.

      Influenza HA is just structurally related to human agglutanins, it’s function on the virus is to bind to particular cells (like those on your airway epithelium) and mediate entry into the cell.

  5. November 3, 2009 4:48 pm

    Ack… apparently I don’t understand the basics of HTML anymore… or at least not in this blog.
    That was supposed to read: “According to Wikipedia, Hemagglutinin is related to the agglutination of blood cells” with a link to

  6. Natacha permalink
    November 3, 2009 11:36 pm

    Hey Kevin, thanks for addressing this for us non-immunologists. There is so much misinformation out there and its hard to form any educated opinions on the matter without doing extensive research which I don’t have the energy or time to do. So thanks for pre-chewing this.
    What I find the most frustrating (as always with this sort of thing) is the kind of propaganda associated with it as well as the the over-simplification of the stories that are being published. It’s hard to know who to believe especially if like me you rely mostly on “masticated” sources of information for this sort of thing. This website ( has further heightened by suspicion that this is being blown way out of proportion when the CDC is not even tracking how many cases of actual H1N1 have occurred.
    I also believe, like Paul stated earlier, that we are powerful beings that affect our own reality, and this media craze seems like just a way of using that power to make this pandemic a reality and further the “all is going to hell” mentality.
    Anyways, thanks for taking the time to address the scientific side of things, I think that the info you shared is so important although it is based on the premise that there is an actual pandemic and I’m choosing to believe there isn’t.
    Good luck on your test!!!!

    • kevbonham permalink*
      November 4, 2009 2:23 am

      Hey Natacha – glad you found my post informative.

      CDC does track influenza:

      You’ll find a bunch of graphs there, but there are a couple that I personally think are important to look at. The first that I think is important is actually at the very bottom, it shows a graph going back 3 years looking at “influenza-like illness,” which just means that it’s hospitalizations that appear to be influenza, even if they’re not specifically identified. What you can see is that this year, not only is the trend already significantly higher than previous years, it’s also rising quickly far earlier in the year.

      The first graph on the page shows that H1N1 is really the only strain of flu currently circulating. The 4th graph down (with the green, purple and yellow bars) shows deaths caused by influenza, and I think you can tell that this gives lie to the people who claim that this disease is not particularly dangerous. We’re not even a quarter of the way through the flu season and there are already nearly as many deaths from flu as normally occurs during an entire season (and even this is a little low, some of deaths recorded in the 2008-2009 season were actually very late, and probably correspond to the spring outbreak of swine flu, you can see that 2nd peak in early 2009)

      Unfortunately, the graph that breaks down deaths by age group doesn’t compare to previous years, but you can find the data, and this swine-flu is killing people in the 18-49yo age range far more than normal flu.

      Hope you find this helpful 🙂

  7. Natacha permalink
    November 4, 2009 5:57 pm

    Thanks for the link Kevin. I looked at the graphs you pointed towards and I still feel this is being blown out of proportion.

    The first graph you mention, regarding the percentage of visits for influenza-like illness, only reflects people’s eagerness to go to the ER at the sign of any flu-type symptom. I see this possibly being a result of all the media craze regarding H1N1, because if people knew for certain that it is just the “regular” flu, they would just call in sick to work, stay home and suck it up until it’s gone, like they do during “regular” years.

    A friend of mine is an ER doctor and we talked about this a few months back when reports of H1N1 were starting. She said the ERs were absolutely packed with people who barely had any symptoms, and that all they did was send them home and tell them to rest. Also, she said that they tested for H1N1 very rarely since the resources for the test were scarce. This makes me question how they’ve gathered the data for the second graph you mention.

    But be it H1N1 or not, the influenza associated deaths this year does appear to be slightly high compared to the previous 2 years (which in my personal opinion is not enough data to compare to). It would be interesting to know what is the protocol for reporting influenza-associated deaths to the CDC and is it possible that more of such deaths are being reported this year because of the panic. Are they going out of their way to link deaths to influenza more than other years because of the possible “pandemic”? I know this is total speculation and bordering on paranoid but as scientists we do know how easy the perception of the recorder as well as the recordee (in this case the sick person and the family members) can skew data.

    In any case, if this data is in fact accurate and un-biased by the eagerness to promote a pandemic mentality and sell more vaccines, it does seem that this year’s influenza could be more hazardous. Obviously only time will tell for sure when more bars are filled out in that graph.

    I’m not saying we should ignore what is going on because it could possibly be an exaggeration, I just feel that the people doing the labeling and reporting might have a hidden agenda. They are promoting fear, and when we live in fear we are a more contracted version of ourselves, making us more prone to getting sick, making unhealthy choices and more susceptible to manipulation. That said, if people really believe that they are at risk of contracting this illness and that their immune system wont handle it because of pre-existing conditions or medical history or just in case, they should probably go out and get the vaccine.

    Anyways, I’ve thought way more about this than I originally intended to… I’m gonna go back to appreciating the gift of life by spending more time with the people I love, paying a visit to the ocean and remembering how magical this world is, eating less processed foods and more veggies, and infusing everything I do with love.

    To those who have been affected by this disease, my heart goes out to them and may they find healing inside and out.

    • kevbonham permalink*
      November 4, 2009 7:01 pm

      The points you raise are good ones; without knowing the exact procedures used to collect the data, it is certainly possible to imagine places where bias could enter in.

      I would just like to make two points:
      1) Saying that people are blowing this out of proportion to get more money on vaccines is probably inaccurate since the government and many of the scientists raising these issues have nothing to gain from vaccine sales (in fact, the government has to pay for them). I would say that the media could be blamed, at least in the spring, but they really haven’t been spending much time on it this fall.

      2) I don’t think the flu will kill us all and I think that fear mongering is irrational and potentially harmful. Still, it takes almost no effort to get vaccinated, and it’s completely safe, so why wouldn’t you do it?

  8. Chadene permalink
    November 12, 2009 1:00 am

    Hey Kevin! I just wanted to say that this is an EXCELLENT and very well written post. And having done exhaustive research for my debate on influenza (not that that makes me special or anything haha) I can say that I whole-heartedly agree with all of what you’ve written 😉 You should really consider submitting this to an op ed section of a newspaper or something, more people should get to read it and benefit.

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