Study: 2010 pertussis outbreak tied to vaccine refusals.

A number of national media outlets, including a network news program, report on the connection between recent pertussis outbreaks and parental vaccine refusals. On its Monday evening broadcast, the CBS Evening Newsreported on the results of a new study published in Pediatrics examined the 2010 California pertussis outbreak that sickened over 9,000 and killed ten, “found it was worst among 39 communities with clusters of kids who were not vaccinated.” According to the report, in communities with higher rates of vaccine refusal, pertussis outbreaks were twice as likely to occur. In 2010, “the percentage of parents choosing to opt out of vaccinating their children for school has tripled from .7% in 2000 to 2.3%.”

        USA Today (9/30, Healy, 5.82M) reports the study used “data from the California Department of Public Health,” to analyze “non-medical exemptions for children entering kindergarten from 2005 through 2010, and pertussis cases that were diagnosed in 2010 in California.”

        The Los Angeles Times (9/30, Macvean, 3.07M) notes between 2000 and 2010, rates for “nonmedical exemptions” in California have “more than tripled, to 2.33%, with some schools reporting rates as high as 84%.” According to the researchers, clusters of exemptions and high pertussis rates “were associated with factors characteristic of high socioeconomic status such as lower population density, lower average family size, lower percentage of racial or ethnic minorities,” as well as income and other factors.

        CBS News (10/1, Jaslow, 3.87M) website adds the study did not investigate the specifics of why parents refused vaccines, but did find “the families were more likely to be of high socioeconomic status.” During a press conference, director of the CDC’s National Center for Immunization and Respiratory Diseases, Dr. Anne Schuchat, said, “Clusters of people with like-minded beliefs leading them to forgo vaccines can leave them susceptible to outbreaks when measles is imported from elsewhere.”

        The NPR (10/1, Shute, 465K) “Shots” blog reports that the California outbreak was not only fueled by vaccine refusal; since “pertussis is a cyclical disease,” protection seems to fade sooner than doctors originally believed. “So many older children vaccinated as youngsters were no longer immune to the bacterium. And many adults had never gotten a booster.”

        Also reporting on the story are the Time (10/1, Sifferlin, 13.4M) “Healthland” blog, HealthDay (10/1, Gordon, 5K),MedPage Today (10/1, Smith, 122K), Medscape (10/1, Lewis, 164K), and the Boston.com (10/1, 1.75M) “MD Mama” blog.