More than half of the 777 new cases of whooping cough reported in California in the two weeks between July 9 and July 21 were minors, according to the state public health department.
So far this year 6,170 cases have been reported statewide.
Children between the ages of 7 and 16 account for the largest number of whooping cough cases. Of the overall total, 3,303 of the cases were among this age group and they have been reported from all over the state.
Public Health officials are most concerned about infants. Babies are not vaccinated until they are six or eight weeks old and are not protected fully until after three doses of the vaccine. So far in 2014, 109 infants have been hospitalized and three have died of the highly-contagious respiratory disease, which is also known as "pertussis."
Among the infected infants and the children 7 to 16 years old, only nine percent had never received the pertussis vaccine.
In Los Angeles County, 1,000 cases have been reported so far this year. Of those, 179 were reported between July 9 and July 21.