About seventy-five percent of U.S. children received the required vaccinations in 2008, up from about half in 2000, reports a new study from the Centers for Disease Control and Prevention(CDC).
"The goal of the study was to look at trends in vaccination disparities over the last nine years to see if the differences between demographic groups are increasing or decreasing. For most of the categorizations of demographics, the disparities had gone down over the last nine years, so it''s a very positive finding," said Elizabeth Luman, Ph.D., a researcher in the National Center for Immunization and Respiratory Diseases at the CDC.
The study appears online and in the February 2010 issue of the American Journal of Preventive Medicine
Luman, a study co-author, and CDC colleague Zhen Zhao, used 2000-2008 phone survey data of parents of 167,086 U.S. children between the ages of 19 months to 35 months. In addition to race, ethnicity, poverty status and participation in national vaccine programs, parents reported whether their children received immunization with the 4:3:1:3:3:1 vaccine series. This series of shots protects children against diphtheria, tetanus, pertussis, poliovirus, measles, mumps, rubella, hepatitis B, Haemophilus influenzae type B and varicella (chickenpox).
"Vaccination coverage in all groups has increased substantially over the last few years," Luman said. For example, coverage rose from 47.1 percent among children who received care from public providers in 2000 to 71.8 percent in 2008.
Although white children had higher rates of immunization than black children did for most study years, after researchers took factors such as poverty status into account, the gap between the two groups did not prove statistically significant.
As of 2008, differences in vaccination coverage rates between socio-demographic groups were "generally small," the authors said in their study.
"Most of the disparities were smaller, but especially racial disparities were reduced to levels below statistical significance. Disparities between those living in suburban and rural areas narrowed by about 4 percent. That''s good news," Luman said. "What we''d like to see is for all children to have equally high access to these life-saving vaccines."
The use of physician records to verify parent reports of vaccination coverage strengthened the authors'' findings, said Bevin Cohen, an infectious disease researcher and project coordinator at the Center for Interdisciplinary Research to Reduce Antimicrobial Resistance at Columbia University School of Nursing. She had no affiliation with the study.
"One of the reasons that rates went up across the board, especially for rural areas, are programs that allow people to get regular coverage," Cohen said. She added, "Improvements in programs such as State Children''s Health Insurance Program (SCHIP) and Medicaid will continue to boost up these rates more than anything else."
American Journal of Preventive Medicine
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Zhao Z, Luman ET. Progress toward eliminating disparities in vaccination coverage among U.S. children, 2000-2008. Am J Prev Med