WOODSTOCK (CBS) — An outbreak of whooping cough in McHenry County’s school system has now spread to the general public, according to the health department.

A total of 79 cases have been reported in 12 communities: Algonquin (1), Cary (35), Crystal Lake (9), Fox River Grove (5), Harvard (1), Hebron (1), Huntley/Lake in the Hills (5), Island Lake (1), Johnsburg (1), McHenry (5) and Woodstock (15); ages range from 3 months to 35 years old.

The county’s last significant outbreak came in 2004 (191 cases); last year saw 9 cases, according to the county health department.

The cases of whooping cough were originally isolated to area schools, mostly at Cary-Grove High School, where more than two-dozen cases were reported last month.

Another walk-in vaccination clinic has been scheduled Nov. 16, 2:30 p.m.-7 p.m., at MCDH’s Crystal Lake office (100 N Virginia Street) to provide the Tdap vaccine for those 11 years and older who have not received it in the last 10 years. The cost is $50.

Pertussis is highly contagious and easily spread from person to person through coughing and sneezing. Symptoms such as cough, runny nose, sneezing and low-grade fever can last several weeks and lead to complications like pneumonia, encephalitis or pulmonary hypertension.

For more information on pertussis, visit http://www.mcdh.info or call MCDH at 815-334-4510.