Low vaccination rates at schools put students at risk

Show Caption Hide Caption Measles vaccination rates too low in many schools Vaccination data obtained by USA TODAY shows that nearly 1 in 7 schools is below the level of vaccinations needed to help stop the spread of the virus. USA TODAY's Meghan Hoyer breaks down the information.

Nearly one in seven public and private schools have measles vaccination rates below 90% — a rate considered inadequate to provide immunity, according to a USA TODAY analysis of immunization data in 13 states.

Hundreds of thousands of students attend schools — ranging from small, private academies in New York City to large public elementary schools outside Boston to Native American reservation schools in Idaho — where vaccination rates have dropped precipitously low, sometimes under 50%. California, Vermont, Rhode Island, Arizona, Minnesota, Florida, Illinois, North Carolina, Virginia and West Virginia also were included in the analysis.

The 13-state sample shows what many experts have long feared: People opposed to vaccinations tend to live near each other, leaving some schools dangerously vulnerable, while other schools are fully protected.

The clusters create hot spots that state immunization rates can mask. In the 32 public elementary schools in Boise, Idaho, for example, vaccination rates for measles in 2013-14 ranged from 84.5% at William Howard Taft Elementary to 100% at Adams Elementary, just 4 miles away.

Some clusters are among people who have philosophical objections to vaccines; other clusters are in poorer neighborhoods, where parents do not stay up to date with their children's vaccinations.

More troubling in an outbreak that has sickened more than 100 people in 14 states: how few states keep records of school immunization rates, despite repeated recommendations from the Centers for Disease Control and Prevention.

"Really, what should concern parents is the microclimate of their child's school or day care center. And we just had no information about it," said Sundari Kraft, who helped push through a Colorado bill last year requiring schools to provide vaccination rates to anyone who asks. The state does not collect or analyze the data.

"We want to look at ways we can better protect our children before we experience a health crisis," she said.

Most states couldn't provide USA TODAY with school-level data. In some states, officials cited health record privacy laws. Others said they didn't keep the figures on schools.

Many of the more than 27,000 schools in USA TODAY's analysis have perfect or near-perfect vaccination rates for kindergartners. More than 1,100 schools in California – about a seventh of all private and public schools in the state – reported kindergarten vaccination rates above 99%. About a quarter of all Rhode Island schools met that mark, as did two-thirds of schools in North Carolina.

In some parts of Virginia, Southern California, North Carolina and Massachusetts, the low rates are because student records are missing, or students have fallen behind on their vaccine schedules. At 19 elementary schools in Los Angeles' Unified School District, so many students are behind in getting their shots that fewer than 20% were considered fully vaccinated at the start of the school year.

One of the biggest reasons for low vaccination rates is the increased use of non-medical exemptions, led by states such as Arizona and California, which both had increases of nearly 70% in exemptions from 2009 to 2013. Nationally, philosophical or religious exemptions have increased 37%, according to the CDC.

"Lack of immunization due to low socioeconomic status, lack of access to health care — those still all pose real challenges," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. "But you can fix the problem" with better access.

The real challenge is when growing numbers of parents who are highly educated and fairly wealthy opt out of vaccines. Osterholm calls them the "educated uninformed."

"That to me is a real growing problem," he said.

Decades after once-feared diseases were largely eradicated in the USA, many parents have grown complacent, said Arthur Caplan, a director of the medical ethics division at NYU Langhorne Medical Center's Department of Population Health. In addition, parents tend to worry more about their kids' welfare than the nation's public health.

"People used to go stand in line to get polio vaccines because they wanted to be good citizens," Caplan said. "Today, some of the non-vaccinators, they want to be a good parent, but they're not worrying much about anybody else."

Experts say the decision not to vaccinate has implications across the broader population — not just in schools but in grocery stores, bus terminals and other public places.

Because no vaccine is 100% effective, communities rely on immunization across large proportions of the population to prevent the spread of communicable disease, said Saad Omer, an epidemiologist and professor at Emory University who studies immunizations.

Such "herd immunity" also protects those who can't get vaccinated, such as infants and those with immune deficiencies.

"If a vaccine is, let's say, 80% efficacious, there's a ... 1 in 5 chance that even if you do the right thing, your kid is unprotected," Omer said.

Although the CDC sets a federal goal for 95% of kindergartners to begin their schooling with MMR (measles, mumps and rubella) vaccinations, many states and school districts fall well below the mark. In 2013-14, 28 states and thousands of schools fell below the federal target. The CDC's target is above the 90% baseline many experts consider as a minimum level for kindergarten immunizations.

The school-level data reveal vaccination choice is even more localized. For instance, in Scottsdale, Ariz., Desert Shadows Elementary School has a measles immunization rate of 85%. Two miles away in the same school district, Liberty Elementary boasts a rate of 96%.

"The bottom line is that vaccine refusers tend to cluster geographically," Omer said. "And what that does is it provides that critical mass of susceptible individuals that can trigger an outbreak."

Most outbreaks have occurred, he said, after someone who is not vaccinated goes to a place where disease is prevalent, then brings it back to the community. "And then the other unvaccinated people act like tinder and start that kind of a fire."

Measles is particularly problematic because it is extremely contagious, Osterholm said.

"Measles presents a challenge where if you have a group of people who are not vaccinated, if that virus gets in there, ... it will find you," he said.

In many states, public health officials don't even know where those hot spots are.

In Indiana, Maine, Arkansas, Alaska and Colorado, state health department officials said they do not keep any internal records showing school immunization rates.

"We do not have reports or vaccination rates by school or school district, so there are no records, reports or spreadsheets (showing vaccination levels)," Indiana Department of Health spokeswoman Amy Reel said.

In 2013-14, only 13 states met federal standards for collecting data on vaccination among school children as part of the CDC's annual nationwide analysis, which calls for a comprehensive survey or a statistically rigorous random sample in each state.

That's unacceptable, Osterholm said.

"We need to know this information. This is a huge vulnerability when we don't have it," he said. "Where they don't exist, I consider it a basic failure of public health."

Contributing: Caitlin McGlade, The Arizona Republic