Influenza is like the Amtrak train of viruses. It rolls around on a fairly predictable schedule, but it’s timing is a bit less precise than the Japanese bullet train. We start to see sporadic cases each year in mid to late November, which increase steadily to a peak in early February, and then decline into March. Its predictability is due in part to the way it travels around the world, like a wave. It is this feature that allows us to manufacture a reasonably effective vaccine each year by observing the wave in other parts of the world before it arrives. Like many other successful viruses, influenza mutates genetically such that each year the strains are somewhat different. That’s why the vaccine is different each year, and why some years it is more effective than others. It’s also important to note that the influenza vaccine does NOT protect you against the two hundred or so other “cold” viruses circulating out there, and that it CANNOT give you influenza as it is not a live vaccine. So why all the fuss about one little virus? Seasonal influenza virus affects people with greater severity and is responsible, on average, for 36,000 deaths annually in the United States. The bulk of these deaths occur in the very young, the very old, and those of us with pre-existing medical conditions like heart disease, chronic lung disease (including asthma), diabetes, etc. Many people say they have the “flu” whenever they get the slightest sniffle, but influenza is different than common colds in several ways. I begin to think about influenza when my patients describe sudden onset of multiple symptoms, “like getting hit by a train.” Often, they can tell me the exact hour it began, and were feeling quite normal before that. Fever (oral temperature greater than 100.5 degrees Fahrenheit) is often present, as well as marked body aches. All viral illnesses make one tired to a certain degree, but fatigue and weakness are much more dramatic with influenza. Then add to this the other typical symptoms of a cold: sore throat, dry cough, runny nose, etc. Nausea, vomiting and diarrhea are more common in children with influenza, but can be seen in adults also. Although you won’t find this in a medical textbook, I ask my patients if they feel like they would rather be dead, with an affirmative answer being a good correlate of influenza infection. Despite the apparent severity of symptoms, the physical examination is usually remarkably unremarkable. There are also several laboratory tests that can help confirm influenza when the diagnosis is questionable. So, with that train whistle nigh, what can you do to avoid getting run over?
Get off the tracks: eat well, exercise regularly, quit smoking, manage stress, optimize treatment of any chronic medical conditions, and treat others with compassion. Wash your hands frequently, especially if you’ve been in public places or around others who are obviously ill. Don’t share cigarettes, food, drinks, lip balm or cosmetics. Get a flu shot. If you think you might be coming down with influenza, see your doctor because if started within 48 hours of onset, there are some medications that are reasonably effective in shortening the course and decreasing the severity of symptoms. If you have a known exposure to influenza, these same medicines can prevent you from coming down with it.
Where do I go for a flu shot?
For the GMC community you can get your immunization on anytime at:
There’s a little black train a coming, coming down the track You’ve got to ride that little black train and it ain’t a gonna bring you back. -Woody Guthrie