Kaiser study details vaccine hesitancy in Sonoma County
A newly released study of Northern California Kaiser patients confirms Sonoma County’s position in the ranks of California regions with high rates of childhood vaccine refusal and youngsters who are missing one or more of the immunizations recommended by the time they reach age 3.
Amid rising concern among medical professionals about a growing culture of vaccine hesitancy nationwide and the resurgence of health threats such as measles and pertussis, or whooping cough, the study identified five geographic areas in Northern California where parental delay or refusal of immunizations are clustered.
The largest by far is an area taking in parts of Sonoma and Napa counties, where 17.5 percent of young patients lacked at least one of the 17 shots recommended for children by 36 months of age, according to the study released today in the medical journal Pediatrics.
It’s not news that Sonoma and Marin counties, in particular, have high numbers of parents choosing to reject some or all of the vaccines commonly given to children in their first years of life.
One Sebastopol couple said Monday it’s a reflection of some parents’ refusal to accept anything at face value without careful examination, when it comes to the lives of their children.
In some areas of west Sonoma County, 1 in 5 children entering kindergarten have obtained personal belief exemptions waiving vaccine requirements, according to past school records. Two Sebastopol-area districts, Twin Hills Union Elementary and Sebastopol Union Elementary, have reported personal belief exemption rates of 40 percent or higher in recent years.
But researchers say the study demonstrates the possibility of using medical records to track vaccination trends in real time and provide information to help focus medical outreach and, potentially, surveillance for outbreaks of disease.
“I think there’s really strong evidence that areas where there are high under-immunization, there is a higher risk of disease outbreak,” especially very contagious ones like measles and pertussis, said Tracy A. Lieu, lead author of the study.
“It’s not just the individual children who have missed their vaccines,” she continued. “It’s a risk that increases for other children even when they are vaccinated.”
The study also is useful in-house because it may help Kaiser doctors tailor education about vaccinations to boost success toward reaching established immunization benchmarks, researchers said. The study was released to the wider medical community because of its implications outside of Kaiser, Lieu said.
The study used electronic medical records for young patients of Kaiser Permanente of Northern California, which included 154,424 children living in 13 counties in and around the Bay Area and the Central Valley, who were born between Jan. 1, 2000, and Dec. 31, 2009.
Any child who missed at least one of the 17 vaccinations recommended by the Centers of Disease Control by 36 months of age was considered “under-immunized.”
The 10-year study also considered whether the parent or parents had declined all vaccinations or were “shot limiting,” meaning a child received all the recommended doses but never more than two at once.
The results showed that high under-immunization rates cluster geographically, with rates of unvaccinated children running between 17.5 percent and 22.7 percent in the five defined areas, compared with 11 percent outside them, during the most recent period, 2010-2012.
The under-immunization clusters included an area about 29 miles wide straddling Sonoma and Napa counties, a small East Bay area between Richmond and San Leandro; another between Sacramento and Roseville; an area covering northern San Francisco and southern Marin County; and a very small area in Vallejo.