The following post was given to me on Facebook. I could use some help sifting some of it.

I do not promote the use of a flu vaccine. But it's not because "the mercury" or "the formaldehyde," but rather because epidemiological studies do not show that there is an actual social/economic or functional benefit to these vaccines. In other words, when we look at two randomly assigned, randomly selected groups of participants (in large studies) where they either get a flu shot, or a control saline shot, it is very true that the experimental group mounts a response, and adequate levels of antibodies to the vaccine can be detected in about 95-99% of the experimental groups, and 0% of the control subjects mount a similar response... which on the surface would strongly suggest or imply that they would also be protected from getting the flu, the problem is that even though they have a high degree of antibody production, when the studies actually follow them for a whole year and look not just at the antibody response (which is a theoretical assessment that assumes they will get sick less often than those without the antibody response) but they actually look at functional measures such as: -how many times they got the flu or flu-like symptoms, and for how many days these symptoms lasted -how many days off from work they took that year -self-reported quality of life in that time frame -self-reported money spent on OTC medications for flu symptoms they had

These feel like unrealistic expectations to me. A vaccine's effect cannot be measured by its effect on a person's quality of life, spending habits, or the emergence of "flu-like symptoms."

All these functional measures turn out to be null. There is no difference. In some groups, the vaccine group actually experienced more sickness (not statistically significant). The point is, while the immune response is there in the experimental group, it seems to actually play no role and have no influence on it's desired effect, namely, keeping people from getting sick with symptoms of flu.

Here the author appears to be arguing with the very mechanism of vaccination. Stimulating an immune response has no role in preventing emergence of the condition. I suspect he is cherry-picking studies to get this conclusion. I have asked for citations, but showing studies to the contrary may be enough.

What is known for certain is that presently, no vaccine for flu has any benefit whatsoever in those under the age of 2. Likewise in the elderly, flu vaccines have shown, for sure, absolutely no benefit. If you find any evidence to the contrary, please let me know.

For elderly, I found this: Were flu vaccines 9% effective for the elderly in 2013?

For 2-year-olds, I recall reading this before, but can't remember the study. What I do remember is that it was a meta-analysis suggesting that more research is needed on children in this age range -- NOT that studies were done and found no effect.

I want to mention right now that there is a difference between "efficacy" and "effectiveness." These terms may seem to convey the same idea to lay people, but they have very different experimental meanings. Efficacy is the ability to show benefit in the test tube. In other words, to detect antibodies. When a flu vaccine study says it has high efficacy, which they all do, it means "we were able to detect antibody production in 95+ percent of the experimental group that got the vaccine." Yes. Bravo. They all do that. All the studies do that and nobody is questioning that. Not even the hippie idiot hugging the oak tree by the creek.

But effectiveness, that means the observed reduction in incidence and risk after the treatment has been given. In this case, a vaccine.

And with all the studies, effectiveness is very very low, if not nonexistent.

I think this person is merely watering the discussion here. He is trying to suggest that effectiveness is all that matters, but the science can only demonstrate efficacy with nothing to connect the two. I'm not certain how to respond to this except to assure the person that I only care about effectiveness.

There are some confounders that many study authors note. Such as, it's known that in children 6 months to around 8 years of age, the flu vaccine appears to help, but often these are not randomly assigned study designs.

I think he is basically saying that he has not encountered a study he likes.

It's possible that, since flu shots are not free, the high socio-economic status parents are more likely to give them to their kids, because a flu shot is not seen as a mandatory need by those who are on a tighter budget, and that alone means you're not getting good data. Is it that the vaccine is helping? Or is it that high SES preferentially selects for healthier kids at baseline.

I am not sure what he is getting at here. My flu shots cost me nothing. They offer them in the lobby of the building where I work. Some of the schools offer them. My doctor doesn't charge me for it. They pass flu shots out like candy around here. The CDC appears to agree. http://www.cdc.gov/flu/protect/keyfacts.htm

Even still, assuming in 6 month olds to 8 years of age it helps, then we should ONLY be really recommending it to them, and not to everyone.

And for the record, the symptoms of a flu "immune response" are in some people indistinguishable from flu-like symptoms. Your chart is a little flawed. You don't always only get a minor fever from a flu shot. And you can indeed have whole body pain, not just in the arm. And with the fever, comes headache. And malaise is very similar to fatigue and weakness.

I don't have the medical experience to know if this is true.

And this is why some people do believe they "get the flu" from the vaccine. Indeed that's impossible, but it's NOT impossible to get indistinguishable symptoms from the flu, due to a vaccine. That's very possible and happens.

And my take home message is not the same as yours. Mine is: the flu shot is at best very very mildly effective, in some groups of people. It is useless in infants, and the elderly (and those are the ones we want it to help the most, because they are at highest risk of actually having serious complications from the flu. And yet they are the ones who benefit the least from a vaccine to the flu. Influenza, in the general population is not a life threatening disease. At all. And the best prevention for it appears to be dietary and lifestyle (exercise). Unfortunately everyone wants a simple answer like a vaccine. Doesn't work that way. Save your money and get a gym membership instead of a vaccine. Make sure you have adequate vitamin D status. Work on sleep habits (this is a huge risk factor for influenza), and eat more vegetables and fruits.

I find this contradictory since he is suggesting that the flu may work for people within the adequate age range to do these things. You wouldn't get a gym membership for a 2-year-old.

  • I was under the impression that flu vaccines do not work for a whole year. That's why the same group of at-risk people are recommended to get a flu shot every year. The measure of effectiveness being used here may be invalid. – Ladadadada Oct 29 '13 at 16:24
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    What is the claim that you want us to examine? – user5582 Oct 29 '13 at 16:51
  • All flu shots cost; the cost just isn't always borne by the recipient. And I am a little skeptical of flu vaccinations myself; not about vaccinations in general, but just because of the apparent low benefit of the flu vaccine specifically (in otherwise healthy individuals). I'll be interested in the answers to this question. – Ask About Monica Oct 29 '13 at 16:51
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    @Ladadadada - flu vaccines do work for a whole year (and probably for several years at least). The issue is that the vaccines vaccinate against 3 particular strains of influenza (I think some are now including 4 strains to improve coverage) and there are lots of different strains that become more or less prevalent over time. The vaccine is changed yearly to include the strains that the epidemiologists think will be most prevalent that year. – Compro01 Oct 29 '13 at 17:45
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    Welcome to Skeptics!. I am putting this on hold while we address a couple of problems: 1) it isn't clear what the claim is. Is it as simple as "The flu vaccination does not reduce flu incidence."? 2) it isn't clear that this is a notable claim. If it is just one person with a whacky idea, it generally doesn't get a guernsey at Skeptics.SE. You don't provide a link, so we can't check. – Oddthinking Oct 30 '13 at 0:27

When my doctor asked me to get a flu shot, the reason he gave me was that it was to "increase herd immunity".

Even if it's not measurably "effective" (in terms of quality of life) for the individual, I expect that it is effective for the "herd". One reason to have the shot yourself, is to (try to) protect other vulnerable people, like infants and the elderly.

Because answers require references, here is one: The vaccination coverage required to establish herd immunity against influenza viruses says,

RESULTS: The required percentage that would have been required to establish herd immunity against previous influenza viruses ranged from 13% to 100% for the 1918-19, 1957-58, 1968-69 and 2009-10 pandemic viruses, and from 30% to 40% for the 2008-09 epidemic virus. The objectives of vaccination coverage proposed in the United States - 80% in healthy persons and 90% in high-risk persons - are sufficient to establish herd immunity, while those proposed in Europe - only 75% in elderly and high-risk persons - are not sufficient. The percentages of vaccination coverage registered in the United States and Europe are not sufficient to establish herd immunity.

CONCLUSION: The influenza vaccination coverage must be increased in the United States and Europe in order to establish herd immunity. It is necessary to develop new influenza prevention messages based on herd immunity.

The principal claim in the OP seemed to be, "It's not worth getting the flu shot: because although it is 'efficacious', it is not 'effective'" -- where, "effective" was defined as "observed reduction in incidence and risk after the treatment has been given" as well as the "functional measures" listed at the end of the first paragraph, and where "effectiveness" was purportedly measured (or immeasurable) in individuals.

Conversely, by talking about "herd immunity", my doctor seemed to me to be saying that it is effective (at avoiding epidemics) when sufficiently many of a population have been immunized.

Even (or especially) if you are a healthy individual and could therefore afford to risk not having an injection (because, you can fight off the flu if you get it), perhaps you should get it anyway to benefit your herd.

On whether it is "effective for the herd", Economic Appraisal of Ontario's Universal Influenza Immunization Program: A Cost-Utility Analysis says,

Main outcome measures were quality-adjusted life years (QALYs), costs in 2006 Canadian dollars, and incremental cost-utility ratios (incremental cost per QALY gained). Program and other costs were drawn from Ontario sources. Utility weights were obtained from the literature. The incremental cost of the program per QALY gained was calculated from the health care payer perspective. Ontario's UIIP costs approximately twice as much as a targeted program but reduces influenza cases by 61% and mortality by 28%, saving an estimated 1,134 QALYs per season overall. Reducing influenza cases decreases health care services cost by 52%. Most cost savings can be attributed to hospitalizations avoided. The incremental cost-effectiveness ratio is Can$10,797/QALY gained. Results are most sensitive to immunization cost and number of deaths averted.


Universal immunization against seasonal influenza was estimated to be an economically attractive intervention.

The measures of "effectiveness" which the OP alleges were conducted include:

they actually look at functional measures such as:

  • how many times they got the flu or flu-like symptoms, and for how many days these symptoms lasted
  • how many days off from work they took that year
  • self-reported quality of life in that time frame
  • self-reported money spent on OTC medications for flu symptoms they had

In contrast the "Cost-Utility Analysis" document (referenced above) argues from the point of view of "cost effectiveness": how much does it cost (to provide immunizations), compared with how many lives are saved, and how much healthcare costs (e.g. from visiting doctors after you catch the flu) are reduced.

The conclusion says that targeted immunization of high-risk populations have been proven worthwhile:

The cost-effectiveness of influenza immunization programs has been demonstrated by numerous economic evaluations of TIIPs, many of which are directly based on clinical trial data. TIIPs have been shown to be cost-effective in children 6 mo and older [29]–[36], adults 50 y and older [37]–[41], working adults [42]–[44], working adult cancer patients [45], pregnant women [46], health care workers [47],[48], high-risk individuals [49], and older adults (65 y and older) [39],[50]–[55] from a health care payer perspective. Most economic evaluations found TIIPs to be not only cost-effective but cost-saving from a societal perspective.

It goes on to say that universal immunation is also "cost-effective", in that on average it saves one year of life for each $10,000 spent.

Ontario's UIIP also prevented 111 deaths, a 28% reduction in mortality. This resulted in a projected 1,134 QALYs gained in total or 0.09 quality-adjusted life days per person vaccinated. Approximately half of all health gains (QALYs) were associated with a reduction of influenza mortality; the other half was associated with reduction in influenza-related morbidity.

The program costs of UIIP are high, approximately double that of a targeted program ($40 million versus $20 million). However, UIIP was estimated to prevent 786 influenza-related hospitalizations, 7,745 influenza-related ED visits, and 30,306 office visits per season. Preventing influenza cases effectively reduced influenza-related health care costs by 52%, saving the health care system approximately $7.8 million per season, so that the net cost of the UIIP program is $12.2 million, or $2.60 per person vaccinated.

Improving herd immunity might not an argument which would convince low-risk individuals in the USA:

The program appears to offer some health benefits, but the relationship between cost and health benefits of universal immunization had not been evaluated. Our study provides evidence that a universal program is economically attractive in jurisdictions with influenza epidemiology and health care costs that are broadly similar to that of Ontario. [...] A health care system similar to Ontario's (i.e., health care systems with one major payer), where the costs of the immunization program and the costs of treating influenza cases are both in the payer's budget, will enable the universal program costs to be partly offset by savings in health care cost.

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    You might find this study useful as evidence regarding "effective for the herd". – Compro01 Oct 29 '13 at 17:54
  • @Compro01 Indeed, my doctor was in Ontario. They're also keen on health-care workers and pre-school teachers getting the shot: perhaps for the sake of their patients/children. Also I guess that if the herd is successfully immune, perhaps it's no longer measurably effective for individuals (because even unvaccinated individuals aren't exposed to the virus, if their neighbours aren't passing it along). – ChrisW Oct 29 '13 at 18:04

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