Surprise! Vaccine Opt-Outs Fueled California’s Whooping Cough Outbreak


Data for California’s 2010 outbreak of whooping cough is in and it is telling parents, as politely as possible, to pretty please, with sugar on top, vaccinate their kids unless those kids have a medical exemption.

The vaccine “opt-out rate” (or rate of nonmedical exemptions to vaccination) is particularly high in California, which saw a 2010 outbreak of whooping cough (pertussis for all you readers who just can’t delight in the simple joys of onomatopoeia) in which more cases of the illness were reported than in any year since 1947. According to the Los Angeles Times, researchers “who looked at the geography of cases suggest that clusters of ‘nonmedical exemptions’ to immunizations were one of several factors in the California outbreak.” The findings were published Monday in the journal Pediatrics.

There were probably some other factors that contributed to the outbreak. An earlier study published in the New England Journal of Medicine suggested that the DTaP (diphtheria, tetanus and pertussis) vaccine loses some effectiveness after the fifth of the five recommended doses. Also, the cyclical nature of pertussis and the improvements in diagnosing the illness lead to more recognized cases.

However, California hosted a whopping one third of all cases of whooping cough in the U.S. back in 2010, 9,120 cases of the illness in total. Researchers from Johns Hopkins Bloomberg School of Public Health and the California Department of Public Health banded together to find 39 clusters of pertussis with high rates of non-immunization, as well as two clusters of pertussis among children entering kindergarten between 2005 and 2010. Guess what? More cases of pertussis occurred within non-immunized clusters of kids than outside them. Who could have ever imagined such a thing??

There’s a socioeconomic twist to this report, too. The nonmedical vaccine exemption rate has more than tripled in California from 2000 2010, rising as high as 2.33 percent, with some schools showing an opt-out rate of up to 84 percent (an estimated 95 percent of a population has to be vaccinated to prevent outbreaks of an illness like whooping cough). Opt-out clusters and high pertussis clusters were, according to researchers, “associated with factors characteristic of high socioeconomic status such as lower population density, lower average family size, lower percentage of racial or ethnic minorities.”

See, America? There’s no need for a class revolution — the rich are doing their very best to destroy themselves.

Unvaccinated children help fuel whooping cough outbreak, data show [LA Times]

Image via Getty, Kevork Djansezian

Inline Feedbacks
View all comments
Share Tweet Submit Pin