EVANSTON, Ill. (STMW) – Evanston Township High School has alerted parents and students to some confirmed cases of pertussis or whooping cough among students.

Pertussis outbreaks are cyclical with a dramatic spike in reported cases typically occurring every four to five years, according to the Evanston Health Department. The bacterial infection is highly contagious and spreads through coughing and sneezing.

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In the fall of 2006, a major outbreak occurred among New Trier High School students, with at least 35 cases reported at the Winnetka campus. Cook County Health Department officials described the spate of New Trier cases that year as “the largest pertussis outbreak in an Illinois school in recent memory.”

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Only about five cases were reported among Evanston Township High School students that year, but both New Trier and Evanston Township high schools responded by offering free Tetanus-Diphtheria-Pertussis (Tdap) booster vaccines at school to halt the spread of the highly-contagious disease on the North Shore.

In a letter sent Thursday, Evanston Health Director Evonda Thomas, Superintendent Eric Witherspoon and ETHS Nurse Lisa Walters urged parents and guardians to contact their health provider if a student has not received an adolescent pertussis booster.

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According to the letter, immunity from pertussis wanes after about 10 years, which means that teens and adults may no longer be protected by vaccinations received as children. Additionally, vaccine-induced immunity is only 60 to 90 percent effective at preventing infection, they said.

While most people recover completely from pertussis, complications can be severe among high risk groups, especially infants under one year and children who have not been fully immunized against the disease.

The school advises parents to keep a student showing symptoms at home and to seek an evaluation by a health care provider.

If whooping cough is confirmed, the student should remain home for at least five days while completing a treatment of antibiotics.

The Illinois Department of Public Health alerted the public this week to a marked increase in pertussis cases, primarily concentrated in Cook and the collar counties. As of Wednesday, there were 275 cases of whooping cough reported in Cook County.

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