California pertussis epidemic, 2010.

Area of Science:

• Epidemiology
• Public Health
• Immunology

Background:

• California experienced a pertussis epidemic in 2010, with over 9000 cases, 809 hospitalizations, and 10 deaths.
• Pertussis, also known as whooping cough, is a highly contagious respiratory disease.

Purpose of the Study:

• To conduct a descriptive epidemiologic analysis of the 2010 California pertussis epidemic.
• To evaluate public health mitigation strategies, including expanded pertussis vaccine recommendations.

Main Methods:

• Evaluation of clinical and demographic data for all reported pertussis cases in California from January 1, 2010, to December 31, 2010.
• Analysis of disease rates, hospitalizations, and deaths by age group and vaccination status.

Main Results:

• Infants under 6 months, particularly Hispanic infants, had the highest pertussis rates.
• All deaths and most hospitalizations occurred in infants younger than 3 months.
• High disease rates were observed in both unvaccinated children and fully vaccinated 10-year-olds, suggesting waning immunity.

Conclusions:

• Infants too young to be fully vaccinated remain at the highest risk for severe pertussis and death.
• Strategies like vaccinating pregnant women and newborns warrant further investigation for direct protection.
• Waning immunity from the diphtheria, tetanus, and acellular pertussis (DTaP) vaccine series in preadolescents requires additional study.