FLUx et Veritas

 In Preventive Medicine Column

 

FLUx et Veritas

I am getting a flu shot, and so are all members of my family- and you should, too. That’s the simple truth in plain light, and unlike this dangerous infection, it involves no flux from year to year. That was my position last year at this time, and it will be my position next year. This is just the right time for an annual booster of light and truth regarding the perennial menace of the flu, and our best defenses against it.

That we need such a booster at all is testimony to several things. First, the truth about flu recedes readily into the shadows of denial, conspiracy theories, and anti-scientific New Age nonsense. A bit of light is just the right disinfectant.

Second, the influenza virus is wily enough to require a reintroduction every year at this time. That’s because the virus changes its protein coat annually, so last year’s strain is yesterday’s news. CDC epidemiologists do all they can to tell us what’s coming each fall. Well, it’s fall- and this year’s verdict is in.

Let’s start with a general primer. The “flu” refers to an upper respiratory infection caused by a small group of closely related viruses. The virulence, or strength of the flu strain varies every year. The illness caused by the virus is never pleasant, but when the strain is very virulent, the illness can be severe. Although the flu, per se, generally does not cause death in otherwise healthy people, more than 30,000 premature deaths each year in the U.S. alone are attributed to influenza, mostly in older adults, the very young, or those prone to complications due to prior illness or a history of smoking.

When the flu strain is especially severe, being the right age or having generally good health make for less reliable defense. The single greatest infectious disease calamity in all of human history was not plague, or typhus, or smallpox- it was the 1918 flu pandemic, which killed as many as 50 million. Those who don’t respect the flu just aren’t paying attention.

There was, of course, no vaccine in 1918 as there is now, and that may partly explain why we have seen no commensurate outbreak since. Vaccination, however, is only protective when we roll up our sleeves, and too few of us do.

Most vaccines provide protection over an extended period of time. The flu vaccine is unique because the influenza germ itself is unique. It undergoes a process known as “antigenic drift” that changes the germ’s surface proteins every year (that’s the “flux”), so that this year’s flu is generally uncovered by last year’s vaccine. The CDC and the WHO track the emergence of flu strains in Asia each year, and develop a vaccine based on the particular surface proteins that predominate. The virus is also subject to more abrupt changes, known as “antigenic shift,” which occur when flu strains mingle with one another, usually in domestic animals, notably pigs and ducks. That is the process that produces pandemic strains of flu with reference to the source: avian, or swine.

Immunization works by priming our immune system to attack the virus by stimulating it with those surface proteins, known as antigens because they “generate” the formation of “antibodies.” The flu antigens in the vaccine look like the flu virus to our immune system. After the vaccine, if we are exposed to the flu, our immune system recognizes the germ as a foreign invader against which it has laid down preparations, and launches a quick and effective attack. When all goes as hoped, the virus is eradicated before we get sick.

In general, it takes our immune system several weeks after exposure to antigens to develop a robust supply of antibodies. Consequently, the best time for flu vaccine is before the bug is established among us. Based on continuous CDC surveillance, that’s now.

In case you are among the many dubious about flu vaccination specifically, and immunization in general, I will address it bluntly. By and large, doubts and conspiracy theories about vaccines are the privilege of the very societies that are the greatest beneficiaries of them. Stated differently, populations succumbing to polio and smallpox don’t tend to fret the theoretical harms of vaccination. We needn’t go so far; high rates of measles, mumps, and rubella tend to make vaccine enthusiasts of parents as well.

There’s another key consideration here, courtesy not of epidemiologists, but the poet and preacher, John Donne: no one is an island. Your vaccine may save someone else’s life. People who can’t get the flu can’t transmit the flu to those most vulnerable to it and its complications.

There is flux in the composition of the virus year to year, but none in the public health recommendation based on science, sense, and the dispassionate light of epidemiology: you should defend yourself and your loved ones from this perennial threat.

-fin Dr. David L. Katz;www.davidkatzmd.com; founder, True Health Initiative

Dr. David L. Katz
DAVID L. KATZ MD, MPH, FACPM, FACP, FACLM, is the founding director (1998) of Yale University's Yale-Griffin Prevention Research Center, and current President of the American College of Lifestyle Medicine. He earned his BA degree from Dartmouth College (1984); his MD from the Albert Einstein College of Medicine (1988); and his MPH from the Yale University School of Public Health (1993). He completed sequential residency training in Internal Medicine, and Preventive Medicine/Public Health. He is a two-time diplomate of the American Board of Internal Medicine, and a board-certified specialist in Preventive Medicine/Public Health. He has received two Honorary Doctorates. Dr. Katz has published roughly 200 scientific articles and textbook chapters, and 15 books to date, including multiple editions of leading textbooks in both Preventive Medicine, and nutrition. Recognized globally for expertise in nutrition, weight management and the prevention of chronic disease, he has a social media following of well over half a million. In 2015, Dr. Katz established the True Health Initiative to help convert what we know about lifestyle as medicine into what we do about it, in the service of adding years to lives and life to years around the globe.
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