Concern that vaccines might cause harm most common reason why parents don't immunize

Concern that vaccines might cause harm was the most common reason given by parents who choose not to have their children vaccinated for preventable diseases, according to an article in the May issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals.

The number of parents of school-age children claiming non-medical exemptions from vaccination requirements has been increasing for the last decade in a number of states, according to background information in the article. Children with exemptions are at a greater risk for contracting vaccine-preventable diseases and may transmit those diseases to children who are too young to yet be vaccinated, people who can't be vaccinated for medical reasons and people who fail to develop protective responses to vaccines. Further, according to the authors, these susceptible children with exemptions tend to be geographically clustered, contributing to the possibility of disease outbreaks.

Daniel A. Salmon, Ph.D., M.P.H., of Johns Hopkins Bloomberg School of Public Health, Baltimore, and colleagues surveyed parents of exempt school children and randomly selected parents of fully vaccinated children from the same grade schools. The survey was designed to determine why parents claim non-medical exemptions and to explore differences in perceptions of vaccines and vaccine information sources between parents of exempt and fully vaccinated children. The surveys were mailed to parents in four states, Colorado, Massachusetts, Missouri and Washington, which allow exemption to vaccination for non-medical reasons. The survey asked questions about parental attitudes on the safety and effectiveness of vaccines, the chance that vaccines might cause harm, their trust in government, public health and medical sources of information on vaccines and their confidence in alternative medicine professionals.

Sixty-nine percent of the parents of the 277 children with exemptions stated that a reason for seeking exemptions was concern that vaccines cause harm. Parents of exempt children were significantly more likely to report low perceived vaccine safety and effectiveness and a low level of trust in the government. They were likely to have a low perception of their children's susceptibility to vaccine-preventable diseases and not to regard those diseases as dangerous. Parents of exempt children were significantly less likely to report confidence in medical, public health and government sources for vaccines information and were more likely to report confidence in alternative medicine professionals than parents of vaccinated children. Most children with exemptions (75.5 percent) had received at least some vaccine, the researchers found, with vaccination for varicella (chicken pox) most often missed (53.1 percent).

"The rates of exemptions are increasing in many states; the concerns of parents with exemptions may also apply to parents who have nonetheless decided to vaccinate their children," the authors write. "To maintain the public health benefit of immunizations, continued efforts must be made to educate the public. Many of the vaccine concerns identified among parents can be addressed through discussions with health care professionals and public vaccine information campaigns."