whooping cough

Nurses Fatima Guillen, left, and Fran Wendt, right, give Kimberly Magdeleno, 4, a Tdap whooping cough booster shot.
AP File Photo/Ted S. Warren

Washington state’s whooping cough outbreak continues to grow. So far this year, there have  been 397 confirmed cases, compared with 85 last year.

Whooping cough is cyclical; it peaks every 3 to 4 years.

California is battling the worst whooping cough epidemic in 70 years.

Nearly 10,000 cases have been reported in the state so far this year, and babies are especially prone to hospitalization or even death.

Six of 10 infants who have become ill during the current outbreak are Latino. There's no conclusive explanation, but there are a few theories that range from Latino cultural factors to a lack of health insurance.