Why is H1N1 so dangerous?

H1N1 is the predominant strain of the flu this year, according to a mid-Missouri doctor.

H1N1 is the predominant strain of the flu in mid-Missouri so far this year, according to a mid-Missouri health professional.

Dr. Lorenzo McKnelly, an infectious diseases physician at Capital Region Medical Center, said this is just the second time H1N1 has been the season's predominant flu strain. The first time was in 2009.

Because H1N1 has only really surfaced once before, people do not have an innate immunity to the strain.

"When you encounter a brand new strain, there is no preexisting degree of immunity. And as such these strains tend to be far more difficult to manage," Dr. McKnelly said.

Dr. McKnelly said there is no way to know which flu strain will be dominant each year. But while other strains usually target the very young or very old, H1N1 can target typically healthy young adults.

"The younger population who have been vaccinated with less frequency, who have been exposed with less frequency to influenza viruses in general, also are more likely to be the severe victims when typically we see the very, very young and the very old," he said.

McKnelly said it takes testing to determine whether a person has the flu, then further testing to determine whether the flu is an A-strain (like H1N1) or a B-strain.

If the flu is an A-strain, it takes further testing to determine if it's H1N1.

McKnelly said H1N1 symptoms mirror those of other strains and include high fever, chills, shaking and shortness of breath.

But there is some good news.

"This year's influenza vaccine matched very, very well to the circulating strain," Dr. McKnelly said.

That means if you got one or plan to get one, you'll likely be protected from H1N1.