Reading The Atlantic magazine’s “Shots in the Dark” article, I paused at this sentence: “When Lisa Jackson, a physician and senior investigator with the Group Health Research Center, in Seattle, began wondering aloud to colleagues if maybe something was amiss with the estimate of the 50 percent mortality rate reduction for people who get flu vaccine, the response she got sounded more like doctrine than science.” (Scientific denialism?)

Actually, I paused earlier, at “What if everything we think we know about fighting influenza is wrong?”

But let’s back up a moment. Amid the novelty of H1N1 lies the more mundane annual death rate from seasonal flu. On average, estimates place the number of people the flu kills in the U.S. at 37,000. (The CDC penciled down 56,000 for influenza and pneumonia combined in 2006.) For context, about 37,000 people die in car accidents each year, and 30,000 are shot to death.

The problem is that the U.S. population is getting older, and one thing no one is arguing is that the flu kills older people. Something like 90 percent of flu fatalities are in the 65-and-older age range. (Children get sick with the flu in huge numbers, but they don’t die from it.)

Flu deaths in absolute numbers have been rising in the elderly, despite a huge increase in senior citizens getting vaccinated. In a 2007 study (by Lone Simonsen, Robert Taylor, Cecile Viboud, Mark Miller, and Lisa Jackson) published in the Lancet, the authors noted that influenza-related mortality rates had not declined since 1980, though vaccination coverage shot up from 15 to 65 percent.

But then there were all those studies between people who got vaccinated and those that didn’t, which showed a robust correlation between vaccination and not dying during flu season. In fact, The Atlantic says, it was too robust. A 50 percent reduction in mortality rates seemed to indicate that the seasonal flu vaccine prevented deaths of all kinds. Yet Jackson says she got brushed off when she brought the topic of miraculous vaccination up: “People told me, ‘No good can come of [asking] this.”

No doubt this was partly in response to the larger “anti-vaccine” movement. If you want to dive down a particularly fraught rabbit hole, Google “vaccine” and “autism.” On Vashon Island, you can read about how antiviral drugs and flu vaccines are “equally problematic,” and that you should stock up on elderflower and other herbs used during the 1918 influenza epidemic that killed over 500,000 in the U.S.

But partly the problem was that since it was commonly accepted that flu vaccines worked and worked well, it would be unethical to run a truly blind experiment and thereby condemn some study participants to death by flu. And it’s true–healthy adults give you a great immune response to a flu vaccine, just as they do to the flu itself. But what Jackson, et al, suspected was that a number of hidden biases were operative in the comparison of the vaccinated and non-vaccinated senior citizens.

Broadly speaking, the healthy elderly were getting flu shots, and frail or ill seniors weren’t.

They ended their 2007 paper with a call for more rigorous study. And then in 2008 Jackson (with Group Health data) provided that study (authored also by Michael Jackson, Jennifer Nelson, Noel Weiss, Kathleen Neuzil, and William Barlow). Also published in the Lancet, Jackson’s study concluded that for the age group of 65-94, vaccination did not reduce the risk of pneumonia (with pneumonia standing in as an outcome of the flu).

So either ducking the flu doesn’t mean you’ll duck pneumonia, too, or the flu vaccine isn’t working on senior citizens, who most need it to work well. But the conclusion the doctors came to is worth underlining because of the popular tendency toward dogmatism and its evil twin, enantiodromia. This is what makes someone–who lives in a world made possible because of effective vaccines–decide to toss “Western medicine” because a vaccine may work better on one age group than another.

We have plenty of options, Jackson and her colleagues said: “These options include the development of more immunogenic vaccines for elderly people, use of larger doses of vaccine, the combining of live and killed vaccine formulations, use of antivirals in a more aggressive manner for treatment and prophylaxis, and indirectly protecting elderly people through increased vaccination of transmitter populations.” That is, if this vaccine is not working as well as we want, we’ll work on making it better.

It’s ironic, but affirming what we don’t know keeps leading us to better decisions.