DES MOINES (AP) — More and more Iowa flu cases have been reported, and officials say the seasonal outbreak could get even worse now that children are back in school.

At least 151 people were hospitalized for flu complications in Iowa during the last week of December. Iowa Department of Public Health Department medical director Patricia Quinlisk said she doubts the tide of illnesses will ebb soon and flu incidences show “all the hallmarks of a relatively bad and prolonged flu season.”

She says people who traveled during the holidays were exposed to viruses that quickly could be spread by children who have resumed classes.