Eleven students were diagnosed with pertussis, commonly referred to as Whooping Cough, during the month of November.

The Los Angeles Department of Public Health reported the last of 11 cases of pertussis on both campuses on Nov. 30. Parents of middle school students were notified of the first case on Nov. 5 and later that month additional letters were sent to all parents warning of the possibility of exposure from siblings or teammates.

All reported cases are now resolved and there have been no new cases this month, Community Health Officer Sandee Teruya said. All but one of the cases were at the Middle School.

Pertussis is a highly contagious respiratory infection that can potentially lead to hospitalization or death. The name Whooping Cough refers to a distinctive sound that an infected person makes after severe coughing.

Over 9,000 cases of pertussis were reported in California in a 2010 outbreak, the most since 1947. The incidence of the disease has risen since 1980 partly due to reduced vaccination rates, according to the Centers for Disease Control. Students diagnosed with pertussis were not allowed to attend school until they finished five days of treatment with antibiotics and obtained written medical clearance.

In addition, students who shared a class or played on a team with a diagnosed student with pertussis were notified separately. Since July 2011, all students entering seventh grade are required by law to show proof of immunization with the TDap vaccine, which protects against pertussis. The medical forms filled out for all students before the start of every school year fulfill this requirement.

However, the vaccine does not effectively prevent pertussis in all cases and the protective effect weakens over time. The CDC estimates that the vaccine is effective in preventing pertussis about 70 percent of the time.

“All these cases had a booster shot,” Teruya said.