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Getty ImagesNearly one-third, or 28%, of adults and children hospitalized with H1N1, also known as swine flu, have asthma. Thats more than any other chronic condition, according to a recent analysis of cases published in the New England Journal of Medicine.

(The next most common complications on the list were diabetes and a weakened immune system, at 15% each.)

“Asthma was the most common underlying medical condition that we saw,” says Seema Jain, MD, a medical epidemiologist at the Centers for Disease Control and Prevention (CDC). Dr. Jains team analyzed 272 people who were hospitalized with H1N1 for more than 24 hours between April and June.

Twenty-five percent were admitted to the intensive care unit and 7% died. Overall, 29% of children and 27% of in adults in the study had asthma, while only about 8% of the U.S. population has asthma, according to Dr. Jain.

Richard Gower, MD, the president of the American College of Allergy, Asthma, and Immunology, says about 25 million people in the United States have the chronic lung condition, including 8 million children.

Asthma is an accident waiting to happen
Asthma is more common in children than in adults, and swine flu seems to strike younger people more often than older ones—a complete flip-flop from seasonal flu.

In the study, 45% of the hospitalized patients were under age 18, and only 5% were 65 or older. “If you are a young adult and you have asthma, you are in double jeopardy,” says Dr. Gower.

For many people, swine flu symptoms include fever, congestion, and possibly nausea, diarrhea, and vomiting, which are some of the symptoms that differ from seasonal flu. (Seasonal flu rarely causes nausea or an upset stomach). Most of the time, the symptoms can be successfully battled with time, liquids (chicken soup, anyone?), and bed rest.

But for people at high risk, including those with asthma, an H1N1 infection can be a different story.

“Asthma is sort of an accident waiting to happen,” says Dr. Gower, who is also an allergist/immunologist at Marycliff Allergy Specialists, in Spokane, Wash. People with asthma are at risk for breathing trouble with infections in general, not just H1N1.

The lungs of people with asthma tend to bronchospasm, meaning they tighten in response to triggers, such as pollen, pet allergens, bacteria, viruses, or other insults. In the case of an infection like H1N1, the lungs produce mucus in response to the germ, and the mucus can get trapped in the narrow airways, setting the stage for pneumonia.

“You add an insult and it just triples, quadruples, gets 10 times worse very suddenly, and flares the asthma,“ says Dr. Gower. “The bronchospasm occurs and it squeezes the airways dramatically down to narrow, narrow passages—and, in fact, closure—and the mucus that is dramatically increased gets trapped and thats a setup for pneumonia.”

So what should you be doing about H1N1 if you—or your children—have asthma?

Take your medication
People with chronic asthma often need to take controller medications that fight underlying lung inflammation. The problem is, they need to take this type of medication every day, even if they are feeling fine. It can help protect the lungs from triggers like infections.

But many people forget to take the medicine or skip doses when they arent having asthma symptoms.

If you have a young child with asthma, make sure they take their medication as directed, says Dr. Gower. It gets tricky if your child is a teen, because they are notorious for skipping asthma medication, and may lie about it too, he says.

Parents need to talk to teens and explain that although they may have gotten away with skipping asthma drug doses in the past, “this is a brand new ball game,” he says. “They really should raise the threshold of their lungs by taking chronic medicines if they have chronic asthma.”

Dr. Gower also recommends that patients have—and use—a peak flow meter, which is a device that you can blow into to gauge lung function.

“It empowers the patient or the parents,” says Dr. Gower. “Even if the patient says they are doing fine and they are giving their best effort to blow into the peak flow meter and its going down and it gets into the yellow zone then into the red zone, thats a real warning sign that that asthma is getting worse no matter what you are doing.”

Next Page: Get vaccinated [ pagebreak ]Get vaccinated
Being in a high-risk group for H1N1 means that people with asthma should get the vaccine as soon as possible, says Dr. Gower.

“They have a vaccine thats good; its made the same way as the regular flu shot thats been out for many, many years, so they really shouldnt worry more about the side effects on [the H1N1 vaccine] than the other one,” says Dr. Gower. “I think its very safe. I think they should take it if they meet any of the criteria.”

Although there is a nasal spray version of the H1N1 vaccine, people with asthma should wait for the vaccine administered as a shot, according to the CDC. The nasal spray contains weakened H1N1 virus and is not recommended for high-risk individuals. The shot contains dead virus, which is safer for asthmatics.

“People with asthma would be a group that would be considered high risk; they should wait for the shot to come out,” says Dr. Jain. “Remember the seasonal influenza shot is available; they should be able to get that.” People with asthma are also at risk from seasonal flu, she notes, so they should get that shot now.

Due to vaccine shortages, people may have to wait for an H1N1 vaccine. Only 28 to 30 million doses will be available in October 2009, according to the CDC. (Earlier in the year, it was estimated that there would be 120 million by then.) Children ages 6 months to 8 years will need two doses of the flu vaccine, which are given four weeks apart.

In the meantime, if you (or your child) have asthma, one of the best things you can do while H1N1 is circulating is to try to avoid infection in the first place, says Dr. Gower.

You may want to consider skipping parties or other events if there will be children attending who could be ill.“You can communicate by phone, congratulate them, but dont go over and step into the lions dens, so to speak, of infection,” he says. He also recommends that parents reinforce public health recommendations to wash hands, and to cover coughs and sneezes.

“You can teach your children that as well and protect others from them and protect them from others,” he says.

Next Page: Get rapid treatment if you do get sick [ pagebreak ]Get rapid treatment if you do get sick
If you do have asthma and get sick with H1N1 symptoms, you should call your doctor, experts say. “They dont necessarily have to go in to see the physician, but they need to contact them if they have high risk conditions,” says Dr. Jain.

However, if its a child with asthma who is not doing well—say, they have a fever of 103° or 104° and are getting worse—Dr. Gower recommends getting help sooner rather than later.

“You can be exposed to things in the hospital, but if youre that sick, with H1N1 going around, and a respiratory flare, I think its better safe than sorry,” he says.

Dr. Jain also notes that her study found that early antiviral treatment of hospitalized patients really helped—the sooner, the better.

Although most of the patients had antivirals in the hospital, they found that those who ended up in the ICU or who died tended to get antiviral drugs (such as oseltamivir, zanamivir, amantadine, and rimantadine) later than others.

“If you look at the timing of it, youll see that patients in ICU or who died were not treated within two days,” she says. “The median time of onset of illness to initiation of antiviral was three days versus five days, so basically the patients who were most sick had a delay in treatment.”

However, zanamivir (Relenza) is not recommended for treating people with asthma because of a risk of side effects, including bronchospasm, according to the CDC.

Dr. Jain says its important to focus on both vaccinations and rapid treatment for very ill patients.

“The main issue here is antiviral use; thats one of our main findings,” she says. “We really would like to emphasize [that] theres vaccination, and thats an important message and thats out there, and you see that in the media, but I think the fact that antiviral also should be utilized in patients who are hospitalized is also key.”