Officials say an infant in San Joaquin County has died from whooping cough.
California is battling the worst pertussis epidemic recorded in the state in seven decades.
Dr. Constance Caldwell with the Yolo County Health Department is puzzled by the spike, because nearly 95 percent of kids in Yolo County public schools are vaccinated.
The vaccine against whooping cough falters after only about three years, a preliminary study suggests, adding support to school rules requiring kids to get the vaccination periodically.
Dozens of students were sent home from school Wednesday and dozens more didn’t even show up after the new deadline for vaccination against whooping cough passed.
Local school districts have issued deadlines for students to get whooping cough vaccinations. See the list of school districts and the deadline for each.