Health officials in McHenry County say a whooping cough outbreak has extended beyond schools and into the general public.
The outbreak now includes 79 cases in 12 towns. Health officials say most cases are in children ages 11 to 19.
Whooping cough is also called pertussis. Symptoms - including a cough with a distinctive whooping sound - can linger for months. It's highly infectious, spread by coughing and sneezing. At high risk are infants and young children who may not be fully vaccinated and the elderly.
The McHenry County Department of Health has scheduled a walk-in vaccination clinic for Wednesday at the department's Crystal Lake office.
The county's last big outbreak of whooping cough was in 2004 when there were 191 confirmed cases.