Flu season is here, and it’s hitting pretty strong, mostly affecting the age groups — 18 to 64 — that are supposed to be least likely to fall ill. But according to a recent study, there’s another group of people that should also be wary of catching the flu. The study’s authors are urging diabetics to get flu shots, as they could be more at risk of getting sick.

“Working-age adults with diabetes appear to have an increased risk of being hospitalized associated with influenza compared to similar-aged adults without diabetes,” said lead researcher Jeffrey Johnson, director of the Alliance for Canadian Health Outcomes Research in Diabetes at the University of Alberta, according to HealthDay. “This increased risk is small (six percent), but nonetheless is justification for targeting adults with diabetes to get vaccinated.”

The study applied to people who fell within the range of 18 to 64 years old. It used data from over 163,000 working-age adults living in Manitoba, Canada between 2000 and 2008. After factoring in diabetic adults who were receiving flu shots and who had other disorders, it found that they were six percent more likely to be hospitalized for the flu.

Although evidence of vaccine effectiveness is weak, having a vaccine effectiveness of as little as 20 percent could be cost-effective, as it would reduce the amount of patients visiting hospitals. For this reason, it “provides a clinical justification for targeted anti-influenza interventions,” they wrote.

According to the Centers for Disease Control and Prevention (CDC), more than 75 percent of people between 18 and 64 years old were diagnosed with diabetes in 2011. And considering that diabetes causes a person to have weakened immune systems and, therefore, aren’t “as strong in defending themselves against disease,” it’s important that they get the flu vaccine, Dr. Spyros Mezitis, an endocrinologist at Lenox Hill Hospital in New York City, told HealthDay.

The H1N1 swine flu is responsible for 99 percent of the cases that are being tested by the CDC, NBC News reported. Adults aged 18 to 64 have been most affected, consisting of more than 60 percent of those hospitalized due to flu-related illness. Yet despite flu illnesses occurring at a higher rate than normal for this time of the year, less than half the population has gotten vaccinated. The CDC advises everyone older the age of 6 months to get a flu vaccine every year since the prevalent strain of influenza virus tends to change yearly as well.

Source: Lau D, Eurich D, Majumdar S, et al. Working-age adults with diabetes experience greater susceptibility to seasonal influenza: a population-based cohort study. Diabetologia. 2014.