Flu and you: Science-based practical tips

There is now good data looking at the impact of humidity, temperature and UV rays on the survival of flu particles. Why did it take so long for these studies to be done? There’s an interesting bit of science history behind that question. It seems that there have been very few experiments looking at flu transmission because there weren’t any good (read: cheap, and non-biting) animal models for flu spread. Even if you could infect one with flu, most animals then didn’t transmit flu to each other, except for ferrets, and ferrets are…well, ferrets. Would you want to stick your hand into a cage full of cranky, runny-nose ferrets?

Me neither.

But someone read an ancient (yes, 1919!) article that mentioned the fact that guinea pigs caught the flu during the pandemic of 1918. Which makes you wonder, doesn’t it? When they were searching for an animal species to be a scientific guinea pig, how is it no one [wait for the thought here, people, I know it’s a shocker] tried actual guinea pigs? Somehow, it appears no one did. Until now. Suddenly, I’m embarrassed for scientists everywhere. But let’s just ignore the 91-year delay, and move on to what scientists have since learned from the suffering of tiny coughing, feverish piggles.

Scientists found that:

1) Flu breeds and spreads optimally in dry, cold weather–specifically at 41 degrees F and 20% humidity.

2) Raising either the temperature to 86 degrees F, or the humidity to 80%, completely stops transmission.

3) Why does humidity make a difference? You get the flu by breathing it in. Flu is transmitted from inhaling virus particles that are floating in the air (not from touching contaminated objects–that’s a cold virus you’re thinking of). As the humidity rises, flu particles surfing in the air collide with bigger and bigger water droplets and then fall, to die on the ground.

4) In guinea pigs, if the animal is in a warm (68 degrees F) place, the guinea pig stops transmitting virus 2 days earlier than if it’s in a cool place–presumably because cool air keeps the breathing passages cooler, allowing the virus to keep replicating.

What this interesting article doesn’t cover are the Flu and You implications, which is where Doc Gurley comes in. Are there any reasonable, practical things you can do, knowing this new information? Obviously, getting a flu shot is your best bet for avoiding the flu. This year, your shot is already waiting for you, with an H1N1 shot included.

But what this research means in practical terms is that we are probably getting the flu when we are mingling with large numbers of people in cool, dry places. When I think of lots of people standing in cool dry air, the image of millions of moms at the elementary school, waiting for pick-up, springs to mind. Also the crowds hanging out at Muni and AC transit bus stops. Plus the fact that it appears that the price of popularity includes getting sick first (hanging out much?). Unfortunately, for most of us, there’s not a lot you can do (or maybe even want to do) to avoid those situations.

But, if I were a teacher, I’d definitely bring in my humidifier and park it in the corner of a classroom. Leaving one humming in the background might just reduce the transmission of all those combined flu particles hanging, exhaled, in the air. Studies have shown that humidifying nursing homes reduces flu transmission – so it’s not just a theoretical benefit. So if you’re a parent, consider sharing this info, as well as the gift of a humidifier, with your kids’ teachers. You don’t need an expensive humidifier – in fact the types that simultaneously heat the air may lead to mold growth in the humidifier (something you definitely don’t want to be blowing into the air you breathe). A good old cheap type of humidifier that you dump out each day and refill is plenty good enough.

Finally, your grandmother was right. You should have soup when you’re sick, because it will make your throat feel better and hydrate you. But now we also know that just the act of making soup, with the pot simmering on the stove and your windows steaming up, can reduce by two days the time you spend shedding flu virus. At least if you’re a guinea pig, that is.

Got a flu tip? Or a guinea pig story? Share yours in the comments section. Are you a fan? You can follow Doc Gurley on Facebook. Doc Gurley is the only Harvard Medical School graduate, ever, to be awarded the coveted Shoney’s Ten Step Pin for documented excellence in waitressing, and is a practicing board-certified internist. You can get more health posts at www.docgurley.com, or jump on the Twitter bandwagon and follow Doc Gurley. Also check out Doc Gurley’s joyhabit and iwellth twitter feeds – so you can get topic-specific fun, effective, affordable tips on how to nurture your joy and grow your personal wellth.

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