FRIDAY, Jan. 8 (HealthDay News) -- Children whose parents refuse to have them vaccinated for varicella are at nearly nine times the risk of contracting the disease as children who are vaccinated, according to a study in the January issue of the Archives of Pediatrics & Adolescent Medicine.
Jason M. Glanz, Ph.D., of the Kaiser Permanente Colorado Institute for Health Research in Denver, and colleagues matched members of the Kaiser Permanente of Colorado health plan who had diagnosed cases of varicella requiring medical care to four randomly selected control subjects each by age, sex, and length of enrollment in the health plan. The incidence of varicella infection was correlated to vaccination refusal by parents in the two groups.
The researchers found that seven of the 133 varicella cases (5 percent) were children of vaccine refusers, while just three of the 493 control subjects (0.6 percent) had contracted varicella. Using conditional logistic regression, the researchers demonstrated a substantially increased risk of varicella requiring medical care among children of parents who refused vaccination (odds ratio, 8.6) compared with children who were vaccinated.
"Children of parents who refuse varicella immunizations are at high risk of varicella infection relative to vaccinated children. These results will be helpful to health care providers and parents when making decisions about immunizing children," the authors write.