Daniela Mejia, a mother, explains why her daughter is one of thousands of young children in San Diego County who aren’t up to date on their vaccinations. Credit: Katie Schoolov, KPBS

When Daniela Mejia’s daughter Julieta was born, the first-time mother was wary of vaccines.

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Nearly 8 percent of San Diego county’s kindergarteners are not up-to-date on their vaccinations. Public health experts say this gradual but long-term trend threatens the well-being of the entire community.
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“I wouldn’t want to have my daughter suffer from any side effects of such a sudden invasion of infectious disease that was just given to her, you know?,” Mejia said. “I’d like her to be exposed slowly to bacterias and viruses and just naturally.”

Because of her mother’s concerns, Julieta, now almost four, is one of thousands of young children in San Diego County who aren’t up to date on their vaccinations.

More than 3,300 kindergarteners — in both public and private schools — began the 2014-2015 school year lacking one or more recommended vaccinations against diseases such as measles, polio and whooping cough, according to an inewsource analysis of data from the California Department of Public Health and the California Department of Education.

That’s nearly 8 percent of the county’s kindergarten population.

[highlight]INTERACTIVE: Click here for a map of kindergarten vaccination rates in San Diego County[/highlight]

And while that represents a decline from the 2013-2014 school year’s rate of almost 10 percent, it’s still an increase from a decade ago when the rate was less than six percent.

Immunologists are raising the alarm about what they say is our collective amnesia over the damage these diseases have wrought in the past.

Dr. Shane Crotty, a professor at the La Jolla Institute for Allergy and Immunology, said a parent’s decision to vaccinate their child is motivated by fear.
“It really comes down to two fears,” he said, “the fear of something happening if you get vaccinated versus the fear of something happening if you don’t get vaccinated.”

As decades of widespread vaccination eliminated once-feared diseases from the collective conscience of American parents, the first fear took preeminence in the minds of some.

“You’re like ‘Well, yeah, OK. I won’t vaccinate because I have this small little fear [of vaccination complications]’ because on the other side you really have no fear of your kid getting measles or polio because you’ve never seen it,” Crotty said.

Mejia believes that vaccines do work and could be right for some children. But the holistic care practitioner and massage therapist said that once she researched their potential dangers, she decided the risks were too great.

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Key points:

1. More than 3,300 kindergarteners–nearly 8 percent of the county’s kindergarten population–aren’t up to date on vaccinations. That’s lower than last year but higher than a decade earlier.

2. Nearly half of kindergarteners who aren’t up to date have non-medical “personal belief exemptions.”

3. Rates of personal belief exemptions are higher in wealthier schools.

4. If vaccination rates fall further, public health experts warn so-called “herd immunity” could collapse, threatening the unvaccinated and vaccinated alike.
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“This is research that one has to do on their own like ‘What are my options?’ instead of out of fear doing what my doctor said,” Mejia said.

That fear of vaccines’ complications (greatly overwrought, say scientists and medical professionals) — and the decisions it leads to — threatens not just the children whose parents choose not to vaccinate but other children as well.

Thinning the herd

So called “herd immunity” is the theory that at some point, enough members of a given population or “herd” are vaccinated against a particular disease that even the unvaccinated are protected.

The precise level at which a group achieves herd immunity varies by disease. For polio, the number usually given is usually around 85 percent. For whooping cough (also known as pertussis), many doctors say 92 percent or higher is required.

Herds can be any group in which members come into physical contact with each other, from a kindergarten class to an entire county.

[highlight]Read our continuing coverage of the whooping cough epidemic and its causes here[/highlight]

Dr. James Cherry, a pediatric infectious disease specialist at the UCLA Medical Center, said maintaining herd immunity is crucial for a community’s well-being.

Cherry used measles as an example. A current outbreak of that highly contagious disease is believed to have originated with a visitor to Disneyland who was not vaccinated. Cherry said measles requires a 95 percent immunization rate to maintain herd immunity.

“When the overall herd immunity drops below that number and down to something like 90 percent, then you’re in trouble because then you’re going to get sustained transmission,” Cherry said.

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Mejia doesn’t believe that her decision not to vaccinate her daughter can affect the well-being of children who are vaccinated.

“If they have the vaccine, doesn’t that mean that they will be able to fight it off?” Mejia asked.

Crotty said that’s a common belief among parents. It’s also wrong.

“If there are unvaccinated kids who are getting sick, that absolutely raises the risk of vaccinated people getting sick because the vaccines aren’t perfect,” Crotty said, mentioning that many vaccines work perhaps 95 percent of the time.

And not every child can be vaccinated before they’re exposed to unvaccinated children.

As an example, Crotty points to whooping cough. Children can’t be fully vaccinated against whooping cough until they’re more than a year old. Those babies’ vulnerability increases when they come into contact with unvaccinated older children.

“Whooping cough kills babies,” Crotty said. “And you can’t vaccinate the babies.”

They rely on herd immunity.

“The way to protect babies under 12 months is to have everybody else vaccinated so you get the herd immunity,” Crotty said.

The same goes for children with autoimmune disorders who can’t get vaccinated no matter their parents’ preferences.

Personal beliefs

The data of vaccination records for kindergarteners shows that personal belief exemptions — the opt-out parents can sign against immunizing their school children — tend to be utilized by higher-income and presumptively better-educated parents.

A recent study 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.

This phenomenon seems to hold in San Diego County, where nearly half of all non-up to date kindergarteners had a personal belief exemption.

In the 2014-2015 school year, the personal belief exemption rate among kindergarteners attending public school was 3.3 percent. The rate among kindergarteners attending private school was 5.8 percent.

The difference was even more pronounced when comparing the  socioeconomic profiles of public kindergartens.

Among kindergarteners attending public schools where more than half of the student population qualified for free or reduced-cost meals, the personal belief exemption rate was 1.6 percent. The rate among kindergarteners attending public schools where half or less of the student population qualified for the benefit was 5.5 percent.

Cherry, the UCLA infectious disease specialist, wasn’t surprised by inewsource’s findings.

“The whole middle aisles of Whole Foods Markets are selling crap,” Cherry said. “And these are the people who go there.”

Cherry noted that Hispanics, whose educational attainment has historically trailed that of white Americans, have the highest proportion of vaccinations against whooping cough of any major ethnic or racial group.

“Because you have a college degree doesn’t mean you understood epidemiology or you understood cause and effect,” Cherry said.

Mejia currently takes Julieta to daycare a couple times a month. She hopes to enroll her in pre-kindergarten next month.

It’s a “co-op” school where Mejia estimates up to date vaccination rates may be as low as 80 percent.

Said Mejia, “So, this is actually a school where more parents share my point of view.”

inewsource investigative assistant Madison Hopkins contributed to this report.

Joe Yerardi is a freelance data journalist for inewsource, where he worked between 2013 and 2016 as an investigative reporter and data specialist. To contact him with questions, tips or corrections, email joe.yerardi@gmail.com.

8 replies on “Fewer vaccinations threaten San Diego’s collective immunity”

  1. People used to feel the way Mejia does about drunk driving. They would claim that they drive very carefully when they’re drunk, so why should they be penalized?

    After a few thousand deaths from drunks on the road, people woke up. The measles outbreak at Disneyland is the vaccine equivalent of death by DUI. Hopefully, people are starting to realize that it doesn’t matter what ridiculous notions of science you have in your head — if you don’t vaccinate your kids (unless they can’t be for medical reasons), you’re endangering them and the general population.

  2. Well-written. Thank you for including the reference to the article published in PEDIATRICS by Dr. Lieu and her colleagues in northern California about cohorts of children born in this region between 2000 and 2011. The authors found that childhood vaccines have been increasingly under-used during this recent decade. I read the article in its entirety. The facts seem to demonstrate that in the region around the San Francisco Bay, the patterns of vaccine under-utilization and refusal are grouped into geographic clusters. In other words, the children born between 2000 and 2011 who were either under-vaccinated or not vaccinated (presumably because parents refused to permit them to be vaccinated at all or insisted that their childrens’ vaccines be delayed to suit the beliefs of the parents) tended to live in specific areas where it could be expected that “herd immunity” would be reduced and therefore endanger all the children living in those areas. Since the authors were scientists, they did not speculate as to why such geographic clusters existed. They merely indicated that discovering how they exist is important and a good project for future research.

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  7. All medical systems – except orthodox or allopathic medicine – look at the human body as a whole and interconnected system. Homeopathy understands disease as a need of the body to rid itself of toxins, and it does so in an orderly and meaningful fashion without attempting to suppress the symptoms. Vaccines introduce vira directly in the bloodstream while the natural way of catching a disease goes through the air passage or the digestive organs, where the local immune defence sets in. Far from preventing diseases vaccines push the disease into a chronic form and deeper into the body, where it then attacks vital organs. The result of suppressing measles and other infectious diseases in this manner is cancer and other autoimmune and chronic diseases.

  8. Since the article mentions whooping cough/ pertussis, I think it is only fair to mention a few things. 1) the CDC, on its own web site, acknowledges that the unvaccinated are not the driving force behind recent outbreaks; 2) an FDA study in 2013 on baboons showed that those who received the vaccination were protected from the illness, but infected other baboons who had not been vaccinated. This may be why they have decided the “cocooning” strategy does not work in Australia (i.e., the strategy of trying to vaccinate all the relatives/ siblings/ etc. of a newborn baby in an attempt to “cocoon” the baby and protect it from pertussis. 3) the infectious diseases expert that Senator Pan, the author of SB 277 trying to eliminate the personal beliefs exemption relied on as a witness, said himself that the pertussis vaccine was “not one of its best success stories”. If you don’t believe me, search online for the Education Committee hearing – it was somewhere in the last half hour I think, after all the public comment. 4) A little education would go a long way when it comes to pertussis. If you have severe coughing spasms that just won’t go away (it can drag on for weeks), you could be spreading pertussis. You can ask to be tested (it’s a nose swab test) at your doctor appointment, and if it is, you should start antibiotics so you won’t spread it anymore. 5) Reactions, while rare, are not as rare as the pharmaceutical industry would like you to think. The whole “1 in a million” thing is baloney. The fact is, they aren’t collecting data on reactions. Oh, there is VAERs, but most doctors tell you it is just a “coincidence” and don’t report it, and most parents don’t even know about VAERs to begin with. My child nearly died after getting the Dtap, which is why I won’t be vaccinating him with it ever again.

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