The flu season is in full bloom across the nation and it is taking a heavier than usual toll on those generally considered at lower risk for serious flu illness.

“This influenza season was particularly hard on younger and middle age adults,” the CDC reported in its weekly Morbidity and Mortality Report on February 20.

“People age 18-64 represented 61 percent of all hospitalizations from influenza — up from the previous seasons. Influenza deaths followed the same pattern; more deaths than usual occurred in this younger age group.”

The CDC reported that flu-related hospitalizations for people age 18-64 this year have already surpassed end of season rates for three out of the last four years.

Sara Robinson, Maine CDC Epidemiologist, reported on Tuesday that influenza is widespread across the state and five new outbreaks were documented at facilities in the last week. The CDC tracks flu outbreaks in schools, nursing homes, hospitals and other institutions, as well as positive flu tests, and flu-related outpatient visits and hospitalizations.

Robinson said this year’s flu season is distinctly different than last year’s.

“Last year’s season started and peaked earlier and was a predominately influenza A/H3 season, which tends to be more severe,” Robinson wrote in an email, “Influenza A/H3 also tends to affect older individuals more than younger individuals, which often leads to more hospitalizations.”

“This year’s season is a predominantly influenza A/H1N1 season,” Robinson wrote, “Since the pandemic of 2009, H1N1 tends to affect more younger individuals, which is holding true this year. Of all the influenza cases reported to us this year, 90 percent are in individuals younger than 65.”

Last year outpatient visits for flu peaked around the Christmas holidays in Maine, but this year, outpatient visits are showing a continued upward trend through January and February. 

“Unfortunately there is not a good way to predict how much longer we will remain at widespread,” Robinson wrote. “As they like to say the only predictable thing about influenza is its unpredictability.”

If you are feeling smug right now for getting your flu shot, you should be. CDC’s data from positive flu test samples show that this year’s vaccine was right on target. The CDC estimated this week that this year’s influenza vaccine reduced the likelihood of a flu-related doctor’s visit by about 60 percent.

Although flu season is in full swing, the CDC continues to recommend vaccination as your best option to protect against influenza.

“It is always a good time to get a flu shot,” Robinson wrote. “We still haven't peaked here in Maine and influenza can circulate year round, so even if you haven't gotten a shot before there is still time.” Robinson said it takes 10-14 days after vaccination for immunity to develop.

And if you’ve had the flu and survived, there’s a silver lining to all that suffering. “If a person becomes ill with influenza and survives they will have immunity to that strain of influenza. However, influenza strains change very rapidly, and it is fairly unlikely that one individual would be exposed to the exact same strain more than once. That being said, there is some cross protection so if an individual has influenza they will likely have some immunity or get less sick if they are exposed to a similar strain in the future.”