Because whooping cough (pertussis) is almost as contagious as measles (affecting ~12-17 individuals with each case), clinicians are required to report cases of this bacterial respiratory tract infection to the state's department of public health. In 2010, California had the highest number of cases of whooping cough in 60 years. A new study scheduled for publication in The Journal of Pediatrics describes the 2010 whooping cough epidemic and details strategies to decrease the incidence of this infection.
Kathleen Winter, MPH, and colleagues from the California Department of Public Health (CDPH) evaluated 9,154 cases of whooping cough with onset between January 1 and December 31, 2010; 809 cases were hospitalized and 10 resulted in death. All deaths and most of the hospitalized cases (62%) were in infants less than 3 months of age, and infants less than 6 months of age had the highest disease rates. In the population aged less than 6 months, Hispanics had the highest incidence of whooping cough. However, in children and adolescents 1-18 years of age, Whites had the highest incidence.
It is recommended that infants should receive 4 doses of DTaP (diphtheria, tetanus, and pertussis) vaccine by 18 months of age, and children should receive whooping cough "booster" doses at 4-6 years of age (DTaP) and 11-18 years of age (Tdap). Adults are also encouraged to receive the Tdap booster because immunity from both the disease and the vaccine wanes over time. The number of cases of whooping cough was elevated in pre-adolescents, even when they are fully vaccinated, indicating that protection from the 5-dose DTaP series may wane before the Tdap booster is given. However, the authors believe that the decrease in cases of 11-14 year olds suggests that Tdap is effective for adolescents.