The proportion of San Diego County kindergartners who are up-to-date on their vaccinations is at its highest level in at least 16 years following the enactment of tougher requirements.

About 2,400 San Diego County kindergartners — in both public and private schools — began the 2016-2017 school year lacking one or more recommended vaccinations against diseases such as measles, polio and whooping cough, according to an inewsource analysis of state data.

That figure represents about 5.3 percent of the county’s kindergarten students.

And while one in 20 kindergartners lacking required vaccinations might seem high, it represents the lowest figure in at least 16 years.

Kindergartner Vaccination Rates

Public health experts say the drop is the result of a new state law limiting the conditions under which a student may enter kindergarten without having received a full slate of vaccinations.

The law, enacted after a measles outbreak at Disneyland in late 2014 sickened more than 100 people, eliminates personal belief exemptions (PBEs) that allowed parents to opt out of vaccinating their children if they hold religious or other nonmedical objections to vaccinations.

About 1.4 percent of county kindergartners had a personal belief exemption in the 2016-2017 school year, down more than three-fifths from the previous year (PBEs have remained valid for this year’s kindergartners who received them before January of last year).

Shane Crotty, a professor at the La Jolla Institute for Allergy and Immunology, said the law known as SB 277 was “definitely” having its intended effect.

“Surely the compulsory nature (of the law) is having a bigger impact than the measles outbreak itself,” Crotty said.

Vaccinations up at many schools

Many of the county’s 509 kindergartens that reported vaccination numbers saw their up-to-date vaccination rates increase.

Exact figures for many schools are unavailable because the state partially masked data for those that reported only a handful of students missing some vaccinations. The data also excludes kindergartens with fewer than 20 students.

RELATED: Click here for a map of kindergarten vaccination rates in San Diego County

Among the kindergartens where exact numbers were released, 141 saw an increase in the proportion of their students that were up to date on their vaccinations. 121 saw a decrease.

Among those schools that saw increases, The Heights Charter school in Alpine saw the greatest percent increase in up-to-date students. Of its 35 kindergartners, 33 were up to date on their vaccinations this school year. Last year, just three of the school’s 24 kindergartners were up to date.

At the other end of the spectrum is Mater Dei Juan Diego Academy. Five percent or fewer of the kindergartners enrolled at the private school in Chula Vista were up to date on their vaccinations (the actual number is masked). The school did not report vaccinations data to the state last school year.

Officials from The Heights Charter and Mater Dei Juan Diego did not return calls seeking comment.

The elimination of the personal belief exemption for new students was the biggest change in the vaccination law.

At least 177 schools — 35 percent of the county’s 509 kindergartens that reported vaccination numbers — did not have a single student with a personal belief exemption. That figure could be even higher as 240 kindergartens had partially masked data. In the 2015-16 school year, 154 kindergartens reported having no students with personal belief exemptions.

Horizon Prep in Rancho Santa Fe saw the biggest decline in personal belief exemptions between the 2015-16 and 2016-17 school year. It went from 13 of 40 students having a personal belief exemption to none.

Susan Ferrari, the school’s registrar and director of enrollment services, said the new law “absolutely” had an impact.

Ferrari said the school made a concerted effort to educate parents about the new rules before they took effect.

“As soon as the law was passed, we started communicating with them so they had plenty of time to become compliant so they would understand the law and how it would affect them,” she said.

The vaccination records for kindergartners have in the past shown that personal belief exemptions tended to be utilized by higher-income and presumptively better-educated parents.

A 2014 study published by the American Academy of Pediatrics found that as the percentage of people with graduate degrees in a neighborhood increased, so too did that neighborhood’s percentage of under-vaccinated children.

Two years ago, when inewsource analyzed 2014-2015 school year data, we found that the personal belief exemption rate among kindergartners attending public school was lower than among those attending private school. A similar pattern held when comparing the student population at public schools with higher and lower proportions of students eligible for free and reduced price lunch.

Given the masking of specific figures for many kindergartens, it is impossible to repeat the analysis this year for all kindergartens.

However, among just those schools where precise figures were provided, the difference between rich and poor schools was erased.

Ways around new requirements

Despite the large reduction in personal belief exemptions countywide, some schools still have a high proportion of students claiming such exemptions. Foremost among them are independent study programs that are not subject to the new law’s requirements.

At Inspire Charter School – South in El Cajon, 315 of the school’s 525 kindergartners have a personal belief exemption.

Inspire is an independent study charter school that has no physical classrooms. Instead, the institution develops educational curriculums that are taught by parents who homeschool their children.

Dr. Nick Nichols, executive director of Inspire Charter Schools, said he’s not surprised by the high number of students with personal belief exemptions. Many parents got their kids’ exemptions before the ban went into effect in January of last year.

“They were all rushing to do it. I imagine it was all over Facebook,” Nichols said. “There’s a certain portion of the population that believes it’s bad or something.”

County Kindergartner Vaccination Rates title="County Kindergartner Vaccination Rates">Your browser does not support inline frames or is currently configured not to display inline frames. Content can be viewed at actual source page: County Kindergartner Vaccination Rates

Sherri Erlendson, chief of staff for the school, said the new requirements might have made homeschooling more attractive to some parents.

“I believe that when it became the law parents started looking for an alternative” to traditional, classroom-based kindergartens.

Ferrari, the Horizon Prep administrator, said that at her school some parents decided to do just that.

“I know for sure we have a couple (families) that are homeschooling because of that or that perhaps had some interest in homeschooling anyway and between the two decided to make that decision,” she said.

Crotty, the immunology professor, said the small number of parents taking advantage of the loophole is unlikely to threaten public health.

“From a public health perspective, you’re probably in good shape. If it was huge swaths of people doing this, yes it’d be a problem but it’s a really rare event,” Crotty said.

FEATURED PODCAST KPBS' daily news podcast covering local politics, education, health, environment, the border and more. New episodes are ready weekday mornings so you can listen on your morning commute.





Sign up for Today's Top Stories newsletter Need help keeping up with the news that matters most? Get the day's top news — ranging from local to international — straight to your inbox each weekday morning. Enter your email address

To view PDF documents, Download Acrobat Reader.