CHAPEL HILL – Flu outbreaks are spreading across our state and the nation, but this year it is impacting age groups who are historically more resistant against the virus, making us wonder what is different this flu season.

WCHL’s resident science expert, Jeff Danner, studied the statistics collected by the North Carolina Department of Public Health and found that it is the H1N1 strain of flu, also known as the Swine Flu, affecting a majority of North Carolinians.

“It is not a higher than normal number, so there’s heightened concern because it is not about the rate of deaths,” Danner said. “What is different about these deaths and what has raised some concern is the age profile.”

Thirteen people have died so far this flu season in North Carolina. Danner said that twelve of the thirteen who died because of the flu were between 25-64 years of age, adding that many are between the ages of 25 and 49.

“Typical seasonal flus tend to impact very young children with underdeveloped immune systems or the elderly who have weakened immune systems. If you look at the age profile of flu deaths each year, they tend to skew younger and older.”

H1N1, which also is carried by pigs, caused a world-wide pandemic in 2009.

The Center for Disease Control estimated that between 8,870 and 18,300 H1N1-related deaths occurred between April 2009 and April 2010.

Now considered a seasonal flu, the H1N1 strain causes symptoms similar to ordinary influenza, such as body aches, fatigue, coughs, runny noses, chills, congestion, and nausea, according to the Fevers of more than 100 degrees are common as well.

The “Spanish Flu” of 1918, another H1N1 strain which caused a pandemic, also resulted in the deaths of previously healthy adults.

Danner explained that a part of what made that the Spanish Flu so deadly was an abnormal immune response to the flu, called a cytokine storm.

In such a reaction, molecules, called cytokines, attack the infected cells in your lungs. The virus can then no longer use the cell it hijacked to make copies of itself.  Consequently, an increased number of cytokines were sent to the lungs and dissolved the lining, causing the victim to suffocate.

Danner said the Spanish Flu of 1918 caused a cytokine storm in many adults with strong immune systems, increasing the number of deaths.

“People essentially drowned in fluid that had accumulated in their lungs. Now, I can’t say that is what is happening now, but that is some of the concern when it is affecting people in their prime of life.”

The good news for everyone is that the flu vaccine also protects against the H1N1 strain.

In response to the flu outbreaks in our area, UNC Hospitals; Rex Healthcare, a UNC subsidiary in Raleigh; and Duke University Hospital have implemented restricted visitation rules.