The results, as reported, are pretty striking: a 50% reduction in heart attack or stroke and a 40% reduction in mortality. And those results seemed to apply to patients both with and without previously diagnosed cardiovascular disease.

If this is real, the question is why? There have been many studies over the years looking at the relationship between infection and inflammation and bad things happening in blood vessels. Some studies have suggested that patients who’d been treated, for one reason or another, with certain kinds of antibiotics over the years seemed to have fewer heart attacks. Researchers guessed that certain infections might predispose to inflammation, and subsequent development of vessel-narrowing plaque, in coronary arteries.

The U.S. Centers for Disease Control and Prevention is telling us everyone should get the flu vaccine every year. Many of us are not listening. I am in the camp of the skeptics, as I am in relation to just about everything. I want to see evidence that the vaccine substantially lowers my statistical likelihood not just of getting influenza but of becoming seriously ill with influenza, and that the magnitude of this benefit greatly exceeds the magnitude of the risk of a serious adverse reaction to the vaccine. Over the years I have found the evidence of such a favorable risk-benefit calculation to be reasonably convincing for older folks and those with chronic diseases (heart and lung diseases and diabetes), but not so convincing for younger and otherwise healthy people.

And I’ve been less than impressed with the scientific evidence that all health care workers should get the vaccine to keep from spreading the flu from their infected patients to others who are susceptible. It makes sense, but the evidence that it really works that way just isn’t compelling. So I get my flu shot to keep my employer happy, but I remain skeptical.

But the idea of other benefits has definite appeal. I often take ibuprofen for various aches and pains. The fact that there is a little bit of suggestive evidence that it reduces the likelihood of developing Alzheimer’s disease suits me just fine. If I’m going to do it anyway, an unexpected benefit is welcome. Now, that is an example of an association that may or may not have causality. No one has done a randomized, placebo-controlled study and followed patients long term, which is what you’d have to do, because that’s a disease that develops over a period of many years.