(Portland, OR) -- Tomorrow is exclusion day in Oregon. That's the day when students who aren't up to date on vaccinations get sent home, unless they have an exclusion. This includes preschools, Head Start, public and private schools. County health departments offer vaccination clinics for kids who don't have health care. Oregon has over one-thousand cases of whooping cough this season, and health officials say a lack of vaccinations against pertussis is the main reason why.