Now that flu season again is closing in on all of us, it’s time to trot out the annual debate about flu vaccines.
On one side are pro-vaccine stalwarts like those in public health (and yours truly), who look at the needle and syringe and see lives saved and hospitalizations averted. On the inevitable other side stand those against vaccination, people looking for plot, conspiracy, and intrigue in all the wrong places: the anti-vaccine brigade. Somehow, the discussion each year begins from scratch, Groundhog Day-style, with identical claims, counterclaims, and mud-slinging from all quarters.
This year, it must be admitted, the discussion is a bit more dicey—the Centers for Disease Control and Prevention announced a few weeks ago that this season’s vaccine is not such a good match, meaning that the vaccine may prevent fewer cases of influenza. On average, the vaccine has an efficacy of about 60 percent. This number is arrived at by comparing proven influenza rates in groups that vaccinated and those that didn’t—a fair-enough and simple-enough way to examine an extremely complex epidemiologic problem.
This year, the vaccine protection rate may be even lower because, even in the red-hot super-cool molecular science world of the 21st century, we still generate flu vaccine like it’s 1963. Here’s the staid approach: In winter each year, certified flu experts meet in a room and decide which of the dozens of strains circulating worldwide are likeliest to cause the most harm when the next winter’s flu season hits, eight to 10 months hence. They look at all sorts of data and then like weathermen forced by the ticking clock to make a judgment despite imperfect information, they vote three or four strains into the vaccine.
The three-strain, so-called trivalent, version had the run of the place for decades until recently, when a four-strainer (quadrivalent) became FDA-approved. The reason so few strains can be accounted for within the annual shot is simple: Each of the three or four targeted viruses requires a certain volume and concentration to be appropriately provocative. To vaccinate against the dozens of potentially circulating strains would require a giant syringe more out of a vaudeville act than a nurse’s station.
Once the three or four viral strains have been selected, vaccine manufacturers go about the long, desperately slow and finicky business of growing the virus up so it then can be killed for the familiar shot-in-the-arm or else weakened (attenuated) for the inhaled version. This takes months and months—a turnaround that’s glacial by modern standards and, though new and improved super-duper fixes are just around the corner, the corner mostly remains in the distance.
Plus there is another problem that the viruses pose—the problem that apparently is the culprit this year—they evolve. In viral terms, it is called antigenic drift and shift— along the double helix that constitutes the influenza RNA (DNA’s poorer, clunkier cousin), a mutation here and there happens the way mutations always happen until after a while, poof, you turn around and you (or your immune system) can’t even recognize the virus anymore. So too with a vaccine that provokes a specific immune response aimed at a specific RNA sequence. With enough changing of the influenza RNA over time, the vaccine no longer provokes the “right” immune response. Rather, all of the manufactured antibodies are all stirred up but have nowhere to go.
This sort of virus-vaccine mismatch happens every few years and, in the world of public-health crises, is pretty low on the panic-o-meter. In fact it might be that a mismatch doesn’t even lead to worse flu years.
The bigger problem is that the anti-vax crowd waits for this sort of mess to pounce, as if the biologic unpredictability of a living virus is enough to make their point. Their point of course is a slippery one: One day it is poor vaccine efficacy; another it’s not efficacy at all but toxicity or side effects such as autism that make the argument against shots; or lastly, the most absurd and therefore best embraced, the argument is that catching the real infection is somehow more natural and health-making—and therefore better for the kid who is sick.
It is this fear of giving the anti-vaxxers a leg up that has stifled any sort of honest discussion about the very real limits of the flu vaccine. Because let’s face it, by modern standards, where measles vaccine and hepatitis B vaccine are 99 percent effective in every study, a report card coming in at 60 percent efficacy is pretty lame.
Though this too is debatable given that 25,000 to 40,000 people a year die of influenza—the vast majority of them unvaccinated. A simple halving of the number with today’s mediocre vaccine would represent a major public-health triumph. By way of comparison, about 14,000 people in the U.S. died of AIDS in 2011—a vaccine to cut that number in half likely would result in a Nobel Prize.
In other words, the anti-vax crowd, basing their debate well outside the corridors of standard science, has somehow pushed the entire public-health discussion of how best to control infectious diseases to a place outside the rational and evidenced-based. And that’s where a flimsy but emotionally effective argument can do real harm by causing an outbreak not of influenza but of deliberate and profound misunderstanding.