According to a new study, kids whose parents say no to varicella (chickenpox) vaccine, are more prone to develop the disease.
The study said that routine childhood immunizations have reduced illness and death related to a wide variety of vaccine-preventable diseases.
But recent trends have suggested that public trust in the national immunization program is declining.
"Expanding childhood immunization requirements and increased media coverage of alleged associations between vaccinations and chronic illnesses have heightened parental concerns regarding vaccine safety," wrote the authors.
"Parents have also expressed concerns that children are at low risk of infection and that many vaccine-preventable diseases are not serious. During the last decade, as a consequence, the number of parents who claimed non-medical exemptions to school immunization requirements has increased significantly," they added.
Dr. Jason M. Glanz, of Kaiser Permanente's Institute for Health Research, Denver, and colleagues studied 133 children enrolled in one health plan who developed chickenpox between 1998 and 2008.
Each case was matched to four randomly selected children who were the same age and sex and had been enrolled in the plan for the same amount of time, but had not developed chickenpox.
Among the 133 children who developed chickenpox, seven (5 percent) had parents who refused the varicella vaccine, compared with three (0.6 percent) refusals among the 493 controls.
"Compared with vaccine acceptors, children of vaccine-refusing parents had a nine-fold increased risk of varicella illness. Overall, 5 percent of varicella cases in the study population were attributed to vaccine refusal. We believe these results will be helpful to health care providers and parents when discussing decisions about immunizing children," wrote the authors.
The findings suggest that if more parents refuse vaccines, the incidence of varicella and related complications also may increase over time, especially among individuals at high risk of severe infection (such as pregnant women, infants and those with compromised immune systems), the authors note.
"These results provide evidence to counter the misperception among some parents that unvaccinated children are not at risk for vaccine-preventable diseases," they concluded.
The study has been published in the current issue of Archives of Pediatrics and Adolescent Medicine.