Well, it wasn't a term that would apply to many people before organ transplants gave people a reason to take immunosuppressant drugs and before HIV started spreading.

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Compromised immune system. A term that was relatively unheard of before the vaccine tsunami.

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Mark Crislip responded to the Atlantic article point-by-point.http://www.sciencebasedmedi...

A randomized placebo-controlled trial shouldn't be unethical.They did it to test polio vaccine.http://www.sph.umich.edu/ab..."In placebo control areas, where vaccine was interchanged with an inert substance, 428 out of 749,236 children contracted the disease."

They're doing it to test malaria vaccine on children.http://online.wsj.com/artic..."The latest study will include two age groups: infants and children five to 17 months old. Half of each group will get the vaccine and half a placebo... Then they will be followed over two years for signs of clinical malaria."

Suppose the vaccine is 60% effective, but there's a 50% chance of getting the placebo. That's equivalent to getting a vaccine that's 30% effective, which is better than nothing.

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I think there might be a disconnect here between what positive effects we should be looking for, and how they are measured. I do not work in the field of flu vaccination, but I have enough epidemiology education that I can tell that the main good points of a vaccine are not being articulated by the CDC, etc.

While a vaccine does theoretically protect an individual, one of the major reasons behind vaccination campaigns is to prevent or slow *an epidemic* -- or the spread of a disease through a group, instead of preventing one person from getting sick. This is a little like voting, because part of the point of democracy is to keep crazy despots from coming into power and wrecking the country, instead of specifically protecting one person's interests.

The economists will tell you that, in a country of hundreds of millions of people, voting isn't worth the time or expense on an individual level, but if not enough people vote (or vote the "correct" way, whichever way you think that is), we could end up with someone running the country who can destroy it.

Similarly, when enough people get vaccinated against the flu, it should slow down the spread of disease enough that, yes, perhaps fewer people get the disease, or it just spreads more slowly. When the flu spreads more slowly, that should decrease 1)the number of opportunities the flu has to mutate into a more deadly flu at any one time, or 2)the chances that so many people will be sick at one time that healthcare facilities are overwhelmed or basic services (like police) cannot be fully staffed because too many people are sick.

We are very lucky today to not understand a deadly epidemic. The flu epidemic in 1918 didn't just kill thousands of Americans--it brought normal life to a standstill, including much economic activity. Other, far deadlier epidemics, such as yellow fever and bubonic plague, resulted not only in unprecedented numbers of individual deaths, but also in panic and disorder that brought down cities. I do not say this to scare people (don't be scared!) but to try to articulate that a true epidemic is not just about sickness but about preventing chaos that can lead to economic and physical safety problems. It is far easier to prevent people from getting a disease through vaccination than it is to prevent people from panicking when a disease hits.

While we haven't had a true flu epidemic in many decades, I don't think we've ever gotten enough people (or the right people--that would be children, food service workers, healthcare providers, etc) vaccinated to actually prevent a flu season, and that has translated to what (I believe) the CDC has estimated as 30,000 annual flu-related deaths a year, mostly among elderly people.

But these costs and benefits are difficult to measure. Since we haven't had an epidemic in years, we don't see the possibilities that vaccination could be preventing--it's like how we don't appreciate how much we need clean water, because we are not routinely sick from not having it. Because we don't have two identical Earths hanging out, we can't tell if our vaccination campaigns slowed down the development of a new flu pandemic, by preventing many chances for different strains to mutate or come in contact with one another. (This is important, not just in delaying a bad event, but in allowing people to develop better Flu treatments. Anti-viral medications have come a long way in the past twenty years.) Finally, those thirty thousand estimated flu deaths may not show up on death certificates, where cause of death will often be the complications of flu, like pneumonia or dehydration.

I completely support people's rights to refuse vaccination, and I hope that I've provided a coherent explanation of the public health reasons for flu vaccination, whether you agree with me or not :)

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But it doesn’t address what to me is the key issue: the lack of a noticeable net mortality effect.

True, but I'm not convinced there is a key issue in the flu vaccine question: there are a suite of issues, which are unfairly jumbled together in the Atlantic article.

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A key distinction is between seasonal and pandemic influenza. There may be no noticeable net mortality effect for seasonal flu shots (assuming the flu doesn't kill youngsters and the shot is ineffective for oldsters). This does not mean that shots won't help in a pandemic in which youngsters die more at much higher rates than by seasonal flu.


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I call in general for costs to be lower, but not below prices.

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If time cost is the main consideration, why not call for making flu shots cheaper (in time)? It seems like we have enough evidence that the flu shot does protect against the influenza virus, but the virus isn't common enough to make it clearly worth the cost.

BTW, in the benefits column, I think you forgot to account for:

eliminating "pain and suffering" caused by the flunot transmitting the flu to your family and othersdecreased probability of contracting other diseases, such as pneumoniadecreased probability of death

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Robin is a "med skeptic" in the sense that he recognizes that spending on medicine has (in aggregate) a stunningly weak correlation to improved health. Robin and several health policy experts discussed this in Cato Unbound, and I'm sure you can find some posts at OB on the topic too.

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I think I've heard that kind of thing mostly applies to "megavitamin" supplements, those that contain a much bigger dose than people would ever get by eating food. A standard "one a day" vitamin shouldn't be enough to overdose on, but I could be wrong about this.

Also, note that Vitamin D was not part of this meta-analysis, is not an antioxidant, and low blood levels of it are associated with an increased risk of death.

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This was the key sentence in the Atlantic article for me:

"Studies show that young, healthy people mount a glorious immune response to seasonal flu vaccine, and their response reduces their chances of getting the flu and may lessen the severity of symptoms if they do get it."

I HATE having the flu; if the cost is 1.5 hours or my time but the benefit is a 1% chance of avoiding five days of being miserable in bed, then that's worth it to me. I'd give it about a three-to-one ratio-- I'd rather spend three hours waiting in the doctor's office than one hour being miserable and feverish in bed.

Also, I have two school-aged children, so I bet my chances of getting the flu are higher than the overall 1% incidence figure.

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The aggregate studies presented here would seem to be less accurate than the regular testing of vaccines that goes on. Simple tests where people are exposed to the virus, with the vaccine at varying levels, are given every year to determine effective dosing. It works!

Using these aggregate numbers it's just too hard to figure out what is causing the correlations.

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I find this statistic, presented barely, to be shockingly high. "Jackson’s findings showed that outside of flu season, the baseline risk of death among people who did not get vaccinated was approximately 60 percent higher than among those who did."

I wonder if confining his research to seniors had any effect, I have a very high suspicion of sample bias here.

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It takes me 1.5 hours to get a flu shot, but having the flu costs me less than 150 hours in lost time.

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Alexander: I wouldn't. If much of Germany is getting vaccinated, you can just be a free-rider. I have heard that it's safer to be unvaccinated, protected by herd immunity, than to be vaccinated without herd immunity.

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I've read (and I can't find the source immediately, but probably someone on SBM) that even a poorly matched flu vaccine can have some efficacy against total mortality. The misconception is that the vaccine operate sas a binary switch (protected from flu true/false). Instead, it is a very analog education of the immune system. It's plausible that a poorly matched shot can still help enough that you don't end up with as many severe complications.

Jefferson makes a good point that there could be confounding bias in the non-blinded trials. But this is NOT the same thing as appealing to non-blinded trials of (say) acupuncture. One difference is that it's very difficult to design a perfect study here (at least, given constraints of ethics). Although as Mark Crislip notes, there have been some good ones that show efficacy.

So, we can't yet demonstrate to our satisfaction that flu vaccines definitely work. Our best guess so far is that they work, but not perfectly. But we have shown they are definitely safe. Given that there are lives at stake, I claim we should proceed as best we can, while still trying to think up better ways to control for bias in future studies.

I think this is one of the two prominent differences between Evidence Based Medicine and Science Based Medicine: In SBM, you are allowed to do what the best available science reasonably suggests is efficacious, as long as it's safe. But you should still be humble and clever and do everything you can to rule out your bias.

(For completeness: the other difference is that EBM can be made to show efficacy for unscientific things, by subtly assuming them to be valid in the formulation of the study. For example if you assume acupuncture can have an effect on pain, you can use EBM to quantify that effect. But you have implicitly facepalmed because your control is too different to rule out bias and placebo effects)

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