We turned to our trusted infectious diseases source, William Schaffner, MD, professor of preventive medicine at Vanderbilt University, for answers to our 2014 flu questions.
What kind of flu are we dealing with this year?
It's the same swine flu strain that has persisted since 2009. And when we say it's the dominant strain, that's dominant with capital "D." According to Centers for Disease Control and Prevention (CDC) typing, more than 95 percent are H1N1.
Where did H1N1 come from anyway? Mexico, right?
Yes, it originated in Mexico in 2009. Most new flu strains come from Asia, but this one didn't read the book; it started out in Mexico, came to us, and moved around the world.
We don't know exactly where it began in Mexico, but it's likely that, as with all new influenza strains, a bird flu got into a pig, and the pig was simultaneously infected with a human strain, and the two mixed their genetics. They exchanged their genes, and what you get out of that mixture is a bird flu–swine flu variant that can now spread person-to-person. The connection between birds and pigs and humans is closer than you would think, at least in flu world.
Where are flu hot spots right now?
Although influenza is present throughout the country, the epidemic is in different phases in different parts of the country. It started in the Southeast, and we're already seeing a tapering off there. But we're really seeing it take off on the West Coast and across the Midwest.
New England and the Northeast have been relatively spared. There's some there, but it really hasn't taken off yet.
Why is the 2014 flu so nasty, especially for young adults?
We can almost turn that around and say why isn't it affecting people age 65 and older. That's because those people, when they were younger, back in the 1970s, encountered a flu virus very similar to H1N1. And those older people have some remaining protection. The current H1N1 flu virus can cause very serious disease even in middle-aged adults, even if they have no underlying conditions. That's just different than the usual flu season, where of course the predominance of deaths are people ages 65 and older.
According to CDC data, as of Jan. 28, the highest rate of hospitalization is in people 65 and older and kids younger than 5, however, of the flu hospitalizations, 61 percent have been people 18 to 64. This pattern is similar to what we saw in the 2009 H1N1 pandemic.
That sounds pretty serious. So who are you telling to get vaccinated?
It's a hard lesson for many middle-aged people because they haven't traditionally had to be very concerned about influenza. But because this flu is causing serious complications across many age groups, it's at the base of the reason why the CDC's recommending that all of us older than 6 years of age should be vaccinated against the flu each year.
It's too late for a flu shot, right?
February is usually the peak month for influenza when you take the whole country into account, so there's still ample time to do damage. So we say if you haven't been vaccinated yet, run, don't walk, because it takes 10 days to 2 weeks for your protection to build up.
Do some people get flu shots just to protect more vulnerable family members?
Getting the flu shot appeals to everyone's good nature. I haven't ever met someone that wants to give flu to someone. Even if they are minimally affected, they can be without symptoms or very few, they're still capable of transmitting flu to other people.
Other people say I'll stay home when I'm sick so I won't give it to others. The strategy is flawed because you are spreading the flu germ, the flu virus, the day before you get sick.
Even though it's not a perfect vaccine, it remains the single best way to prevent flu and serious complications.
But don't some people get the flu after getting the flu shot?
You may get a little bit of a sore arm, and 1 to 2 percent of people get a low fever. If you're older than 65 and receiving the high dose, you may feel a little more muscle soreness and feel crummy or washed out for a day.
None of that has anything to do with that old myth that you can get flu from the flu vaccine, which is, of course, erroneous.
Speaking of the flu shot, wasn't there a study finding some people getting the flu shot actually came down with narcolepsy?
That was a European flu vaccine. I don't think we know exactly why that happened, but that vaccine was never licensed for use in the U.S.
We hear bird flu is stirring up in China again. Do we need to be worried about that here in the U.S.? A lot of our readers raise backyard chickens—is that a concern?
That's something clearly we in public health keep our eye on and watch very carefully. At the moment, fortunately, this bird flu virus doesn't have capacity to spread readily from person to person. At the moment, there's no threat here. It's completely contained to Asia at the moment.
As for anything to do with live chickens in the U.S., there's no need to be concerned at the moment.
For more must-know flu info, check out 25 Foods That Fight Cold & Flu.