The percentage of Kansas students entering kindergarten in 2012 who had been immunized on the medically recommended schedule tumbled to 61 percent from about 72 percent the previous year.
The drop, highlighted in KIDS COUNT data released Tuesday by Topeka nonprofit Kansas Action for Children, puts on-time immunization rates at their lowest in at least five years.
“Timely immunization not only keeps children healthy but also protects others, including infants who are too young for vaccinations and people with compromised immunity,” said Shannon Cotsoradis, Kansas Action for Children president and chief executive officer. “It also prevents the spread of dangerous diseases that can lead to serious illness and even death.”
The vaccination rates in the study pertain to a series of five shots children are recommended to receive by age 2: diphtheria-tetanus-pertussis, polio, measles-mumps-rubella, hepatitis B and influenza B.
Prior to 2012-2013, on-time vaccination rates increased every year since the 2008-2009 school year, when they checked in at 63 percent.
Gianfranco Pezzino, Shawnee County's health officer, said Kansas is prone to large fluctuations in vaccination rates from year-to-year and said he hoped the KIDS COUNT numbers were a one-year anomaly.
He said the state is failing to reach the 90 percent coverage recommended for “herd immunity” that prevents infectious disease from spreading to unvaccinated people.
“We’re way far away from that number, and it looks like we’re getting even farther away if this drop is true,” said Pezzino, who also works for the Kansas Health Institute, the parent organization of the editorially independent KHI News Service.
Cotsoradis said there was limited margin for error within the data, which was gleaned from the Kansas Department of Health and Environment's 2012-2013 Retrospective Immunization Coverage Survey. She pointed to confidence intervals for the individual vaccines that generally allow for a difference of about 2 percentage points.
Cotsoradis also agreed that vaccination rates fluctuate from year-to-year in Kansas. But she said a plunge that caused the five-year immunization outlook to trend downward probably could not be chalked up solely to one poor year.
“Could there be some volatility? Yes, absolutely,” she said. “But that much volatility? I doubt it.”
Cotsoradis said there's other evidence that supports the data's accuracy, including outbreaks of pertussis and measles in recent years.
Delay increases risk
Some of the dip in on-time vaccination could be attributed to parents not getting their children all of the recommended shots, Cotsoradis said.
Some also could be due to an increasing number of parents delaying some shots. Reports of parents delaying shots due to concerns about the safety of the current schedule have proliferated in recent years, and a 2009 study found 26 percent of parents surveyed delaying vaccinations, despite no evidence the current schedule causes more adverse reactions.
KDHE data showed that about 71 percent of Kansas children had completed the recommended series by 35 months of age, meaning roughly 10 percent caught up on their shots within a year of the recommended time frame.
Still, Cotsoradis said delaying vaccination increases risks.
“Although the data suggests that some children may receive these immunizations at a later point in time, it’s important for kids to get these vaccinations by age 2 to reduce the risk of exposure not only for themselves but for others,” she said.
There’s also the possibility more parents are opting out of vaccinating their children.
“KDHE told us there has been a significant increase since 2010 of religious exemptions,” Cotsoradis said. “But they are not releasing that data until next year.”
There are two ways to enroll a child in kindergarten without the requisite vaccinations. One is a medical exemption, which requires a form signed by a physician stating the reason for the exemption and which vaccines it pertains to.
The other is a religious exemption that requires a parent or guardian to write a statement explaining that the child is a member of a religion that opposes vaccines. In Kansas, that is far more common than the medical exemption.
Clusters of exemptions
KDHE’s 2012-13 Kindergarten Immunization Coverage Survey reported last year that 363 of the 481 exemptions exercised during the 2012-2013 kindergarten year were for religious purposes.
The 481 total exempted represented just 1.4 percent of the state's overall kindergarten enrollees that year, but many of them were clustered in the same communities, increasing the possibility of outbreaks. KDHE reported that three of the state's 283 school districts had 10 percent or more of their kindergarten students with an exemption.
Anti-vaccine activists in Kansas sought a third, broader exemption based on personal belief in the 2012 session, but it died in committee. Colorado has such an exemption, but pro-vaccine groups argue it fosters disease and sought to tighten it last spring.
KDHE's kindergarten immunization coverage report showed the western part of Kansas has the highest vaccination levels, while "the counties and (school) districts with the greatest percentage of exemptions are concentrated more heavily in the eastern half of Kansas."
The report, compiled by epidemiologist Elizabeth Lawlor, calls vaccine coverage a matter of “great public health importance” and says falling vaccination rates have coincided with a rise in once-dormant diseases.
“When children are exempt from vaccination (or not up to date) and they are in close contact of someone with a vaccine preventable disease, they are at risk for contracting the disease, and subsequently spreading the disease to unimmunized or under immunized individuals (e.g., infants),” the report states. “Therefore it is important that the percentage of exemptions in school-aged children remain low.”
Cotsoradis said it might be time for the state to put immunization rates back on the front burner, perhaps bringing back the Immunize Kansas Kids task force.
“I think in recent years there has not been a lot of statewide attention to our immunization rates,” she said, “generally because they’ve been better and stable.”