Flickr photo by Ryan Boren
Seven of the 12 California counties with the highest whooping cough rates also have above average rates of kindergarten students showing up to school with "personal-belief" vaccine waivers, a California Watch review of state data shows.
The state’s emerging whooping cough epidemic took center stage yesterday when a state public health official called on those caring for infants to get vaccines and to immunize children.
Clearly, the ailment is reaching epidemic proportions not seen since the 1950s, according to state public health officials.
But what's less clear is how much the ailment is being spread by the 10,280 California kindergartners whose parents cite personal beliefs in declining to immunize them last year.
Last month, I reported on the high rate of cases in Marin County, where the county’s health officer pointed to personal-belief vaccine exemptions as a possible culprit.
The Bay Citizen expanded on my piece in an article in the New York Times, talking to Marin parents who declined to immunize their kids.
The controversy over kids and vaccines tends to pit public health officials, who favor vaccines, against jittery parents uncertain about the role that shots play in unexplained increases in autism and similar disorders.
Researchers took a global look at how personal-belief waivers drive whooping cough in a 2006 article in the Journal of the American Medical Association. They found that states – like California – that have easy-to-obtain-vaccine waivers saw a 90 percent higher incidence of whooping cough than other states.
"States must balance parental autonomy with the tremendous public health benefit of vaccines when considering the types of exemptions allowed and how policies are implemented," the report authors wrote.
If lawmakers are paying attention, the first place to look seems to be affluent and, by most measures, thriving Marin County.
Marin has the state’s highest rate of whooping cough infections at 77 cases per 100,000 residents. And its personal-belief exemption rate is also more than twice the state average, with 7 percent of kindergartners showing up to school with no shots. (You can check out whooping cough case and personal-belief waiver data in the spreadsheets below.)
Statewide, just more than 2 percent of kids enter kindergarten without shots because of personal beliefs.
The trend seems to hold in San Luis Obispo County, which comes in just behind Marin County in its rate of whooping cough cases, with 72 per 100,000. And its rate of vaccine-free kindergartners is twice the state average at 4 percent.
The picture is less clear, though, in Fresno and Madera counties. They take fourth and fifth places in terms of whooping cough-infection rates. Yet both have a low rate of personal-belief exempted kids, at about 1 percent.
Looking at the 20 California counties with whooping cough rates above the state average of about 4 cases per 100,000 people, it’s a draw. Ten of those counties have more kids than the average state personal-belief exemption rate. Ten have fewer.
There’s another confounding factor to all of this. Counties with tiny populations, like Nevada (No. 1 in "personal belief" waivers), Del Norte and Siskiyou counties, tend to cluster to the top of rate lists, confusing the total picture. And larger counties seem to lag behind in their reporting (unless Los Angeles is truly seeing fewer whooping cough cases this year than last).
Oh, and another twist: Some California schools have vaccine exemption rates as high as 70 percent, a DPH spokesman told ABC News. According to that report, 175 schools have exemption rates of 20 percent or higher.
The final answer, perhaps, lies in a close look at the data, examining exactly where the vaccine exemptions and whooping cough cases meet.
The data below is from the California Department of Public Health. The first spreadsheet shows the number and rate of whooping cough cases by county in 2008 and 2009.
The second spreadsheet shows the percent of kindergarten students in each county that enter school without vaccines due to personal-belief waivers signed by a parent or guardian. I sorted both sets of data by rates, from high to low.