DES MOINES, Iowa (AP) — Polk County’s medical examiner says he’s seen four times more flu-related deaths so far this season than he saw last winter. Dr. Gregory Schmunk said Friday he’s received 12 death certificates since November citing flu as a main or contributing cause of death. Schmunk says he received just three such certificates last winter. The Des Moines Register reports three are death certificates of children, most others of the elderly, and one of a 47-year-old.

Schmunk says the spike in flu deaths shows the seriousness of this year’s outbreak, when the height of flu season hasn’t yet hit. The county medical examiner’s office doesn’t receive all death certificates, but Schmunk says he estimates that he sees more than half of Polk County’s death certificates, which is Iowa’s most populous county.