In 2008 there was a measles outbreak in San Diego, Calif. It was the largest such outbreak in San Diego since 1991.
Researchers from the Centers for Disease Control and Prevention and the San Diego County Health and Human Services Agency tracked the outbreak and found it had been initiated by a seven-year-old boy whose parents had intentionally not vaccinated him against the disease. The researchers reported their findings in the current issue of the medical journal Pediatrics.
In January, 2008, the boy who was infected with measles returned from Europe with his parents unaware that he had the illness. Ultimately, 839 people were exposed to measles and 11 additional cases occurred. All those were among unvaccinated children, including an infant too young for vaccination who was hospitalized as a result. In addition, 48 exposed children too young for vaccination were quarantined.
The researchers noted that in interviews the majority of parents who declined vaccination for their children were concerned about adverse effects of the shots. They concluded that “despite high community vaccination coverage, measles outbreaks can occur among clusters of intentionally under-vaccinated children, at major cost to public health agencies, medical systems and families.”