Download 2016-10-07 FLUx et Veritas

Preventive Medicine Column
October 7, 2016
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