5-Shot Friday for 12/15/17: About That Flu Shot…

Dec 15, 2017


5 Shot Friday

5-Shot Friday for 12/15/17: About That Flu Shot…

The other day, a patient sent me a message: what about the news that the flu shot is only 10% effective this year?

At first, I thought, Internet exaggeration strikes again, why can’t there be more news stories that educate rather than mislead folks?

So I looked – and found an article in the New England Journal of Medicine, from just 2 weeks ago.

Short version

The 2017 flu season is in full swing in Australia, with nearly 4 times the number of cases as during the 2009 pandemic, and the vaccine effectiveness against the predominant H3N2 strain is estimated to be only 10% effective. And that’s the same H3N2 strain that’s in our 2017 North American flu vaccines.

Well, alrighty, then.

Longer version

Australia isn’t the U.S., and it’s not clear that the same thing will happen here. But there’s nothing quite like real-world data, and it’s reasonable to think that we will see more cases of The Flu, even with folks who’ve been vaccinated.

Of interest, however, is speculation that different vaccinations might work considerably better. Most flu shots are made using egg-based production methods, and when the virus grows in chicken eggs, it changes slightly, possibly just enough to decrease the effectiveness of the final product:

“In the United States, most influenza-vaccine viruses are propagated in eggs…During the egg-based production process, the vaccine virus acquires amino acid changes that facilitate replication in eggs, notably changes in the hemagglutinin (HA) protein that mediates receptor binding. Since the influenza HA is the primary target of neutralizing antibodies, small modifications in this protein can cause antigenic changes in the virus and decrease vaccine effectiveness.”

There’s evidence supporting this idea: a study on the 2016 influenza virus that demonstrated poor responsiveness to the strains in the egg-based vaccine, but a strong antibody response to viruses from a non egg-adapted vaccine.

And, yes, there are non-egg based flu vaccines available in the U.S., and have been for some time: Flucelvax and Flublok, neither of which derive their H3N2 part of the vaccine from egg-sourced viruses.

So, conclusions

1. The Party Line still holds

Get the flu shot – any flu shot. Even with marginal protection, the CDC has always said that some protection is better than none. Influenza is a serious, contagious, and potentially lethal lung infection. 650,000 people die from it worldwide each year, and around 40,000 Americans (or about a dozen 9/11s). Being under the weather for a few days is preferable to being in bed or the hospital for a few weeks – or worse.

2. You may want to rethink which flu shot you get

If the speculation in the NEJM article is correct, the egg-culture based (standard) flu vaccines may not be as immunogenic and protective as the cell-based (Flucelvax) or recombinant DNA (Flublok) vaccines. Your regular doctor may carry them, but if not, check the websites (www.flucelvax.com and www.flublok.com) and input your zip code to find pharmacies near you that do.

3. These alternative shots are for adults, only

You must be 18 or older to get them, younger folks still need to get standard flu shots recommended for their age range. They’ve not been proven effective in teens and children; in one study cited in the Flublok package insert, the vaccine seemed to underperform the regular vaccine in children under 3.

4. An ounce of prevention

Is still worth a pound of cure. Vaccines definitely fall under the heading of prevention, but so does using hand sanitizer alcohol gel after touching surfaces in public, keeping your hands and fingers away from your face, and being prudent about close contact with folks coughing up a lung. There’s a reason why folks in Asia wear masks in the winter, and it’s not for the pretty colors.

5. Finally, be thoughtful of others

If you’re sick, stay home. Don’t share the wealth, your colleagues and friends will not appreciate you “toughing it out” to carry your weight so they won’t have to. The Flu will put you on your back soon enough, but not before you infect everyone in your area.

And please, don’t go see The Last Jedi if you’re hacking your brains out. That’s just wrong.

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