LOS ANGELES (FOX 11) - Students arriving Wednesday morning at Harvard-Westlake School knew to be vigilant about warding off contagious germs. One student even wore a black mask over his mouth so he wouldn't get sick.
Since November 2018, a total of 30 students across the school's two campuses have come down with the whooping cough - a highly contagious disease which may first seem like a respiratory infection or flu. Eventually, the sickness develops into a cough that sounds like a whoop.
One student said his friends who got sick were out of school for two weeks.
Los Angeles County health officials said they were monitoring three clusters of whooping cough cases across the area, specifically infecting ages 11 to 18 who share classrooms and carpools.
Overall cases have not increased over the last five years, but officials issued a health alert in the wake of the recent cases.
Health officials say vaccines wear off after five to 10 years, but the infection can be treated with antibiotics. According to the Department of Public Health, it is particularly dangerous and even deadly for infants, who end up in the hospital about 50 percent of the time after contracting the illness.
School officials notified students and parents about the recent cluster.
Harvard-Westlake's community health officer has been coordinating directly with the Department of Public Health and that agency is confident about the steps being taken to prevent further spread of the illness, according to a school spokesman.
The schools have also reinforced more disinfecting of germs on campus and will send students home at the first sign of sickness.
City News Service contributed to this report.