So, if you have asthma, what do you need to know to protect yourself?
CBS News medical correspondent Dr. Jennifer Ashton said people with asthma are at such high risk for H1N1 complications because they are at high risk for respiratory complications.
Ashton said people who have asthma have lungs that are more susceptible to inflammation. If their lungs are infected with any upper respiratory infection, such as H1N1, they are then more prone to pneumonia and asthma exacerbation, which can turn into more critical health issues, Ashton said.
"People with asthma should have a treatment plan for how to control their symptoms," Ashton said.
In addition, some of the steroid drugs people take to control their asthma can suppress their immune system, Ashton said, placing them at greater risk for infection and possibly serious disease by H1N1.
Also, antivirals prescribed by your doctor such as Tamiflu can be effective, but not Relenza because it carries a risk of breathing problems.
Ashton said it is highly recommended for people with asthma, or any other underlying condition, to get the H1N1 vaccine in shot form - not the nasal spray. With asthmatics, especially, the shot is key, Ashton said, because the nasal spray can trigger an asthma attack.
"The spray contains a live, but weakened virus, so they really have to get the inactivated form," Ashton added. "And if they think they're suffering from any kind of asthmatic exacerbation, they need to see their doctor and aggressive treatments sooner rather than later."
If you have asthma and get flu-like symptoms, Ashton said, call the doctor right away.
She said, "You don't want to put that off."