Monday, September 19, 2011

Do We Need a Flu Shot?

I'm puzzled about the flu shot situation this year.

I get a flu shot every year. I have asthma, so I'm in a high-risk group. And I hate being sick. Being slammed by the flu on Christmas night a few years ago (there was a vaccine shortage that year) was a nightmare I don't care to repeat. It was horrible, and it took me weeks to recover. I don't need to see Contagion. I was Contagion.

If it's not one of those miracle years when my doctor has enough vaccine to give to her high-risk patients, I'm happy to wait in line with my fellow citizens in some South End church basement for a free shot. My husband always gets a shot, too.

Shots don't bother me. It doesn't take much common sense to know that vaccines are generally very safe. And they protect not only those who get them; they keep the virus from spreading to others. I believe flu shots are a moral responsibility: besides spreading the virus when you're sick, you can be a carrier without symptoms and infect others without knowing it. Including fragile people who could get sick enough to die.

Of course, you can still get the flu — a milder version, or a different strain — even if you had a shot. My point is, we have to do our best to protect each other and ourselves.

I have zero patience with people who go around bragging, "I don't need a flu shot — I never get the flu." What, were you touched by an angel and declared naturally immune? Show me your guarantee, please. I never got the flu either, until I got the flu. And if you ever happen to be a carrier and infect my 97-year-old dad, or my elderly uncle with COPD, or a baby, an ICU nurse, or a pregnant asthmatic, I'm going to be looking for you in the Afterlife (if there is one), when all things are known (which they'd better be — or what's the point?).

But I digress. Every year, the pathogen professionals at the CDC get together to vote for the three viruses they feel are Most Likely to Be Popular and cause an epidemic. Those three vaccines are combined for the coming year's shot. Usually, each year's shot is a different combination of three vaccines, which is why we need annual shots. (Or so I thought.) But this year is a fluke: the 2011–2012 shot contains the same three vaccine viruses as last year.

I regarded this as sort of a vaccine snow day. We already have the correct antibodies floating around in our bodies, so why would we need to get more? You either have antibodies or you don't — right? We don't need DPT, polio, or MMR shots every year, after all.

But the CDC still wants us to get this year's flu shot, even if we had it last year. Does this mean that flu antibodies vanish after a year? Are flu shots that wimpy? Or is the CDC simply worried that we'll become lazy about getting shots in future years because we were allowed to skip a year and are too dumb to get back in line when the annual vaccine changes again?

After questioning friends who either changed the subject or professed ignorance, I finally consulted the CDC's web site. I found this:
Although influenza vaccine strains for the 2011–12 season are unchanged from those of 2010–11, annual vaccination is recommended even for those who received the vaccine for the previous season. Although in one study of children vaccinated against A/Hong Kong/68 (H3N2) virus, vaccine efficacy remained high against this strain 3 years later, the estimated efficacy of vaccine decreased over the seasons studied (6). Moreover, several studies have demonstrated that postvaccination antibody titers decline over the course of a year (7–10). Thus, annual vaccination is recommended for optimal protection against influenza.
So there we have it: Flu vaccines are wimpy. It appears that we don't build up a collective immunity from all the many shots we've gotten over the years; immunity fades over time. Judging from the titles of the four studies that paragraph cites, it seems that if you have a compromised immune system, your ability to produce flu antibodies is possibly compromised, too. That makes sense to me.

But what a drag.

South End church basement, here we come.

1 comment:

  1. PSST: You didn't hear it from me, but if you get a medical record number from Mass General, you can walk in during any of their flu shot clinics in the lobby of the Wang ambulatory care building and get one for free. To get a med rec number, just call the main number and ask for patient registration. Tell them you are getting a physician referral and need one or are participating in a research study. They actually don't care why.

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