More Than 4,500 Whooping Cough Cases Reported in California

On Friday, California health officials announced that about 1,100 cases of pertussis, or whooping cough, have been reported across California in the past two weeks, bringing the total number of cases in the state this year to 4,558, the Los Angeles Times' "L.A. Now" reports.

Of the cases this year, 84% occurred among individuals ages 18 or younger. In addition, 63% of the 142 cases requiring hospitalization occurred among individuals ages 4 months or younger (Brown, "L.A. Now," Los Angeles Times, 6/27).

Marin, Napa and Sonoma counties have had the highest rates of the disease this year (Aliferis, "State of Health," KQED, 6/27).

Gil Chavez, an epidemiologist with the California Department of Public Health, said three infants have died this year after contracting the disease.

Chavez cited three potential reasons for the uptick in whooping cough cases in the state:

• Epidemics of the disease are cyclical and occur every three to five years;
• The whooping cough vaccine's effectiveness wanes over time; and
• Individuals do not become immune to the disease after contracting it (Plevin, "Impatient," KPCC, 6/27).

He said that vaccinating pregnant women during their third trimester "is the most important thing that can be done to protect infants" because newborns are too young to receive the inoculation ("State of Health," KQED, 6/27).