Medical experts are warning that the country could face a "syndemic" as the weather cools and COVID-19 and flu cases begin to rise.

According to the Centers for Disease Control and Prevention, syndemics are epidemics that interact with each other in ways that increase the adverse effects on communities that face systemic inequalities.

Raj Rajnarayanan, assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Arkansas, told Fortune in a recent interview that the United States is a "sitting duck" when it comes to the threat of a syndemic.

"Strained hospital capacities, workforce exhaustion, burnout, a lack of effective therapeutic tools, poor communication, a lack of compliance [with COVID-19 precautions], a lack of continuity planning, and the pervasive influence of social determinants of health" hampers the country's health care infrastructure, according to Rajnarayanan.

Prominent COVID-19 modeler Jay Weiland told the magazine he has "little doubt" that cases will surge this winter, saying that there's a "reasonable chance" the number of cases will surpass the winter spike seen last year when the Omicron variant emerged.

"Last year really showed what happens when we go a few years without seeing our normal viral trends," said Dr. Karen Acker, a specialist in pediatric infectious diseases at New York-Presbyterian Komansky Children's Hospital.

"It may take some time for viral levels and the immunity dynamic to level out," Acker said. "This may be another bad year."

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