Feb 10 2014

Anti-Flu Vaccine Rants at the HuffPo

The Huffington Post continues to be a venue for all sorts of pseudoscience, alternative medicine propaganda, and anti-vaccine sentiments. Two recent posts by Lawrence Solomon in the HuffPo Canada indicate that the nonsense is international.

His first article claims that the majority of health care workers “resist” or “refuse” the flu-vaccine – therefore it can’t be that great. The second attacks the CDC estimates for the number of flu-associated deaths. Together they demonstrate how a bit of motivated reasoning can seem like actual journalism when in fact it leads to misinformation.

Solomon cites statistics about low rates of flu-vaccine update among healthcare workers:

In the UK, only 46 per cent of health care workers — slightly less for doctors (45 per cent) and nurses (41 per cent) — are vaccinated for the flu, despite concerted government efforts according to Public Health England. This startling failure is similar to that seen in Canadian jurisdictions for health care workers today, and those seen in the recent past in the U.S.

The numbers are actually much more variable, and depend highly on a large number of variables. Solomon did nothing to explore those variables, despite the fact that there is much published on the topic. He simply assumed that not getting vaccinated was “resisting” or “refusing” the vaccine.

In fact, health care workers (HCW) cite a number of reasons – feeling that they are healthy and therefore not at risk and lack of time, in addition to those assumed by Solomon of concerns about the lack of efficacy and safety of the flu-vaccine.

Simple measures, such as simply encouraging HCWs to get vaccinated, increase rates significantly (in this NHS study to 68.7%).

Also, Solomon is making an implied argument from authority (and not an appropriate one). Not all HCWs have any significant expertise in vaccines or infectious illness. The flu and the flu vaccine are a complex topic, and the data is difficult to sift through. HCWs appear to be easy to convince that they should be vaccinated, but left to their own devices may not properly sort through the complex data for themselves.

In fact, a little bit of knowledge can be counterproductive, in that you know enough to ask questions and be scared, but not enough to be reassured by a thorough understanding of the data. In fact, at St. Jude’s Children’s Research Hospital, giving their employees accurate information about the flu and the flu vaccine (without mandating vaccination) increased compliance rates among their HCWs to 93.8%.

HCWs are still people and are susceptible to misinformation and fearmongering just like anyone else. Most of them are also not experts in the flu. However, if you give them accurate information about the flu vaccine, compliance rates can be extremely high.

But how serious is the flu? How many people a year does it kill? This is an admittedly difficult question to answer. First, we can only estimate the number of people who get the flu, since most people who get a flu-like illness are not tested to confirm which virus is causing their illness. However, the CDC uses epidemiological calculations to estimate how many people with flu-like illness likely have the actual flu.

Also, asking, “what is the cause of death” is a complex question. Do you mean the first thing that initiated the chain of events in a person’s death, or the ultimate cause of death, or contributing factors without which the patient would have likely survived?

If we are concerned about the impact of the flu and the potential benefit of the flu vaccine, then the latter definition is most relevant. We want to know how many extra deaths there are in a year due to the flu. If someone has a heart attack, and they get the flu and ultimately die of their heart attack, but would have survived without the extra stress of the flu – it is reasonable to consider that a “flu-associated death.” Of course, we cannot know with certainty who would have survived without the addition of the flu, and that is again why we must rely on epidemiological estimates.

The Center for Disease Control (CDC) estimates that between 3 and 49 thousand people die of the flu each year in the US. Solomon criticizes these estimates, and tries to substitute for these numbers based solely on death certificates, as if this is somehow an absolutely objective measure:

The numbers differ wildly from the sober tallies recorded on death certificates — by law every certificate must show a cause — and reported by the official agencies that collect and keep vital statistics.

Death certificates are prone to massive underreporting and therefore underestimating true causes. For example, if the ultimate cause of death was a heart attack, that may be written on the death certificate without any indication that the patient also had the flu which contributed to their death.

The CDC are also not the only ones to estimate flu deaths. Solomon would have his readers believe the CDC numbers are inflated as part of a conspiracy to scare people into vaccine compliance. However, scientists not connected to the CDC come up with similar estimates. In this study, US flu deaths between 1979 and 2001 were estimated to average 41,400 per year.

Solomon also claims that the CDC is using an inappropriate definition it made up:

“Cause-of-death statistics are based solely on the underlying cause of death [internationally defined] as ‘the disease or injury which initiated the train of events leading directly to death,'” explains the National Center for Health Statistics. Because the flu was rarely an “underlying cause of death,” the CDC created the sound-alike term, “influenza-associated death.”

This is nonsense – the concept of flu-associated deaths is generally accepted, and as I described above is an attempt to capture the most meaningful statistic. If, however, you are unfamiliar with medical terminology and reasoning, you can make anything seem odd and imply it is a conspiracy.

Conclusion

Mark Crislip has written extensively at Science-Based Medicine about the flu vaccine. Here is his recent summary:

As vaccines go, the influenza vaccine is not our best and brightest. It has variable efficacy in different populations and because there are new strains every year re-vaccination is required. Those who need the protection the most are those who are least likely to respond. And we have never had enough of the population vaccinated at any one time to take advantage of herd immunity, even supposing an excellent antigenic match between the vaccine and circulating strains.

Overall it appears to be a modestly effective vaccine when used as part of a nutritious breakfast. It decreases the chances of getting flu, of having a flu-like illness, and of having complications of flu such as heart attacks and the need for hospitalization. It is not a great vaccine but it is better than no vaccine.

The current vaccine is not perfect, but it is a net benefit, and it is far better than nothing (critics often fall for the Nirvana fallacy – it’s not perfect, therefore it’s useless). Despite accusations that those who promote the flu vaccine are all hype, when you read what we actually write it is quite circumspect, balanced, and evidence-based. It’s just that the evidence is very complicated.

When you read what those of an anti-vaccine bent tend to write, that is where you find the hype and distortion.

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