Shouldn’t we all be dead by now? We have lived for a few years amid a torrent of reports about the clear and imminent danger of epidemic flu (avian, swine, novel H1N1, whatever). States have passed laws requiring vaccinations for some groups and have stockpiled antiviral flu medications. We even had Hollywood churn out the creepy movie Contagion in September, all in preparation for the Big One.
And yet here we are in late January, when people should be hacking and sneezing and aching, and flu activity is, according to the Centers for Disease Control and Prevention, at “relatively low” levels. Which raises the interesting question: did all of our preparation and worry and taxpayer dollars actually do something?
Not a chance. Flu epidemics are notoriously hard to predict and track. Remember the 2009 pandemic? It started in Mexico (a new wrinkle) in April (also new) and was caused by a strain never seen or imagined before. But don’t expect this to deter people who are looking for explanations for this winter’s flu cool-off. Public-health types are far too alarmist to predict an entire low-activity season—especially since they know that the peak flu season is usually early to mid-February—but others are already offering explanations and, presumably, preparing “you can thank me later” proclamations.
Like maybe it’s the warm winter, be it courtesy of La Niña or global warming. For years, scientists have set out to tag influenza variability to climate change. The connection seems logical: viruses, like people, must have a favorite temperature and humidity and, since winter is when the crud usual-ly hits, influenza must like the cold. If this were the case, maybe global warming would drive down flu infections. But, while weather is surely part of the complicated flu package, warmness didn’t stop the 2009 pandemic, which was brought to the U.S. by high-school kids who spent their spring breaks south of the border. And most scary strains of influenza arise in sweltering Southeast Asia.
Others posit that this winter’s low flu rate could mean vaccination campaigns are working. Dream on: according to a recent Rand survey, only about 40 percent of adults nationally take the flu vaccine, far short of the number required to provide the “herd immunity” needed to decrease flu rates. And it certainly has nothing to do with everyone’s new favorite cure-all, Purell. If it did, other viruses transmitted the same way (various cousins of influenza with Greco-Latinate names like parainfluenza and meta-pneumovirus) would be disappearing too. But they’re not.
In fact, what we are seeing here is the dark secret of medicine and public health: the fact that we usually have no clue why something, good or bad, is happening. We can do our best to fight outbreaks as they arise—and it’s becoming easier with new tools like Google Flu Trends—but we just about never find the smoking-gun DNA. Instead of looking so hard, perhaps doctors, patients, and everyone in between should accept that we are mere spectators to an inscrutable alliance of virus, animal, and climate, a longstanding collaboration that we cannot, as yet, influence—though getting that flu shot might help.