More parents have been refusing vaccines in recent years than a decade ago, according to surveys of pediatricians by the American Academy of Pediatrics published in Pediatrics Aug. 29.

Further, the proportion of doctors choosing to dismiss vaccination-refusing families doubled between 2006 and 2013, the survey found.

“In a busy practice, vaccine refusals and delays occur daily (if not multiple times per day),” wrote Catherine Hough-Telford, MD, of the University of Alabama at Birmingham and her colleagues (Pediatrics. 2016 Aug. 29. doi: 10.1542/peds.2016-2127 ).

“From the perspective of the pediatricians, parents who delay vaccines may do so because of concern for their child’s discomfort and concern about immune system burden, whereas vaccine refusers are more likely to believe that vaccines are unnecessary,” the authors wrote. “Pediatricians report that they continue to provide education to vaccine-refusing and delaying parents at high rates.”

Dr. Hough-Telford’s team compared the national AAP Periodic Surveys of 2006 and 2013 that dealt exclusively with immunizations to learn how currently practicing pediatricians perceived three issues related to vaccination: the prevalence of vaccine refusals and delays, why parents refuse or delay vaccines, and the decision of doctors to dismiss families who refuse to vaccinate.

The researchers excluded pediatricians who did not routinely administer vaccines or otherwise adhere to the Centers for Disease Control and Prevention–recommended immunization schedule for their patients. The 2006 survey had a response rate of 52.6% and included 629 final respondents; the 2013 survey had a response rate of 52.7% and included 627 respondents.

The proportion of pediatricians reporting parental refusals in their practice increased from 74.5% in 2006 to 87% in 2013 (odds ratio, 2.29; P less than .001). These pediatricians estimated in 2013 that 8.6% of their patients refused at least one vaccine, compared with 4.5% in 2006. Similarly, 2.5% of parents refused some vaccines in 2006, the physicians reported, compared with 4.8% in 2013. Those refusing all vaccines increased from 2.1% in 2006 to 3.3% in 2013.

A perceived 73.1% of parents refused vaccines in 2013 because they regarded them as unnecessary, the pediatricians reported, compared with 63.4% in 2006. But parental concern over autism and/or thimerosal dropped from 74.2% of vaccine-refusing parents in 2006 to 64.3% in 2013. Further, the parents refusing vaccines because of safety/side effects concerns dropped from 73.7% in 2006 to 66.6% in 2013, and those worried about their children receiving too many shots more than halved from 42.1% in 2006 to 17% in 2013. Concern among parents about their baby being too small to receive vaccines also dropped.

Physicians estimated that 7.3% of their parents wanted to delay one vaccine, 7.1% wanted to delay multiple vaccines, and 4.3% wanted to delay all vaccines. Urban, inner-city pediatricians were less likely to have parents requesting delays than were parents in other areas, but requests for vaccine delays were geographically similar across different U.S. regions. Only the 2013 survey included questions on delaying vaccines.

Pediatricians reported that 75% of their patients wanted to delay vaccines to reduce discomfort to their child, and 72.5% wanted to delay because they perceived too many vaccines would overburden their child’s immune system.

The percentage of pediatricians who always dismiss patients who continue to refuse vaccines increased from 6.1% in 2006 to 11.7% in 2013; they cited a lack of trust between physician and patient as a major reason (87.4% in 2006; 79.9% in 2013). Further, 80.5% of pediatricians reported in 2013 (the only year asked) that they dismissed vaccine-refusing patients out of concern for their other patients.

Despite no notable geographic differences in dismissals in 2006, the 2013 survey revealed that pediatricians in the West had three to four times greater odds of dismissing patients than those in the Midwest and South. Suburban pediatricians had three times greater odds of dismissing patients than did urban physicians.

The research was funded by the AAP and the CDC Childhood Immunization Support Program. Dr. Kimberlin was a site principal investigator for two multisite studies conducted by GlaxoSmithKline and Gilead.