02/11/2014 08:44 am ET Updated Feb 11, 2014

A Good Reason To Get Your Flu Shot

Eunice Harris via Getty Images

If flu cases seen at Duke University Hospital so far this season are any indication, it pays to get your flu shot.

Researchers from Duke examined the first 55 patients who needed treatment because of the flu at Duke University Hospital between November 2013 and Jan. 8, 2014, and found that most of them had not received a flu shot.

Specifically, among the 22 patients who had to receive care in the intensive care unit, just two had received their flu shots. And among the 33 patients who received care from the regular hospital wards, just 11 had received a flu shot (and of those 11, many had conditions, such as having an illness, being immunocompromised, or being on a vaccination-weakening medication).

"We observed a high percentage of hospitalized patients for influenza requiring ICU level care, which appears higher than observed in our hospital during the 2009 pandemic flu season," study researcher Dr. John W. Hollingsworth, M.D., an associate professor of medicine at Duke, said in a statement. "It remains unclear whether the high rate of ICU admissions represents a diagnosis bias or whether the severity of illness being caused by the current H1N1 virus is higher."

The study, published in the American Journal of Respiratory and Critical Care Medicine, also showed that most of the patients evaluated in the study were infected with the H1N1 strain of the influenza virus (infamously known as "swine flu"). Some of the patients had also tested negative for the flu during a rapid influenza test when they were in fact positive for the flu, which researchers noted could have meant they weren't given the necessary anti-virals.

The median age of patients seen at Duke also skewed quite young, at 28.5.

This year's flu season -- for which H1N1 seems to be the prevalent strain -- has been difficult on the 18-to-65 age group; the flu is usually harder on children and seniors over age 65. Reuters pointed out that this age group also had a low rate of flu vaccination during last year's flu season -- just one-third were vaccinated -- which could spell trouble if the same happens for this year's flu season.

While flu vaccines are not 100 percent effective -- their efficacy is more around 60 percent -- "vaccination is the best prevention strategy that we have," Dr. Alicia Fry, who is with the Centers for Disease Control and Prevention’s Influenza Division, told NBC News.