From Pediatric Supersite.

There are a number of factors that contributed to the recent pertussis outbreak in California, including waning immunity to diphtheria and tetanus toxoids and acellular pertussis vaccines and a lack of vaccination among certain populations. Howard Backer, MD, MPH, who is director of the California Department of Public Health, said the best way for pediatricians to assist in halting the outbreak is to encourage parents to ensure their adolescent?s immunizations are up-to-date in compliance with a new California law that went into effect earlier this year.