Objective: To evaluate progress in timely vaccination coverage associated with low-income households.
Design: The US National Immunization Survey.
Participants: Children aged 19 to 35 months living in low-income households who were sampled between 1995 and 2007 (N = 232 318). Low-income households had an annual income that was 133% or less of the federal poverty level, and high-income households had an annual income of 400% or more of the federal poverty level.
Main outcome measures: Administration of 4 or more doses of diphtheria, tetanus, pertussis (DTaP-DTP) vaccine; 3 or more doses of polio; 1 or more doses of measles, mumps, rubella (MMR); 3 or more doses of Haemophilus influenzae type b (Hib); 3 or more doses of hepatitis B; and 1 or more doses of varicella vaccines by age 19 months as reported by the children's vaccination providers. Progress in timely coverage was evaluated by tracking changes between consecutive annual birth cohorts born between 1994 and 2004.
Results: Among low-income children, timely vaccination coverage increased significantly between consecutive birth cohorts by an estimated 0.5% for DTaP-DTP, 0.3% for polio, 0.6% for MMR, 1.2% for hepatitis B, and 5.3% for varicella vaccines but did not change significantly for the Hib vaccine. Disparities in timely coverage for low- vs high-income children declined significantly between consecutive birth cohorts by an estimated -0.3% for MMR, -0.3% for hepatitis B, and -0.5% for varicella vaccines, did not change significantly for the polio vaccine, and increased significantly by 0.4% for the DTaP-DTP vaccine.
Conclusions: Disparities in vaccination coverage associated with low household income persist. Further progress in timely vaccination may be achieved by improving health care providers' reminder/recall systems, implementing educational interventions that address barriers to vaccination, and increasing parents' awareness of the Vaccines for Children Program.