Whooping cough outbreak in California is being said the result of parent's refusal to vaccinate their children, according to Yahoo! News.
Researchers analyzed local rates of children entering kindergarten with "non-medical" vaccine exemptions, meaning parents or guardians applied for an exemption from school policies requiring vaccines due to personal beliefs, rather than for medical reasons. They compared these rates with rates of whooping cough in 2010, the year the state experienced a whopping cough outbreak that caused 9,120 cases and 10 deaths from the disease.
The researchers identified 39 areas, or clusters, with high rates of non-medical exemptions, as well as two large clusters of whooping cough (also called pertussis) cases. More cases of pertussis occurred within the exemption clusters than outside of the clusters, the study found In addition, areas within exemption clusters were more than twice as likely to overlap with pertussis case clusters than areas outside of exemption clusters. The results held even after the researchers took into account factors that could affect disease rates, such as population density.
San Diego County had a particularly high degree of overlap between clusters of exemptions and pertussis cases. There were 980 pertussis cases in the county, and the area in and around Escondido, a city in San Diego County, had more than 5,100 exemptions. Many factors likely contributed to the 2010 California pertussis outbreak, including increased detection of cases, the fact that pertussis activity increases and decreases in cycles, and that protection offered by a new version of the pertussis vaccine wanes more quickly than that of the previous vaccine.
But the new findings suggest that vaccine refusal played a role as well, the researchers said. Although the overall rate of vaccination in California remained high (90 percent of kindergartners in 2010 were fully vaccinated), some regions had lower immunization rates, the researchers said.
