BACKGROUND:
Achieving and maintaining ≥90% coverage for universally recommended vaccines among young children is a Healthy People 2010 objective.

OBJECTIVE:
We projected the potential improvement in up-to-date (UTD) vaccination coverage achieved by one simulated additional provider visit.

METHOD:
We used 2003 National Immunization Survey data to calculate baseline UTD coverage among 24-month olds for the 4:3:1:3:3:1 and 4:3:1:3:3:1:4 series (includes four pneumococcal vaccinations). We then simulated coverage if incompletely vaccinated children received one additional provider visit to obtain up to four missing vaccinations.

RESULT:
Baseline UTD coverage for the 4:3:1:3:3:1 series was 69.1% (95% confidence interval [CI], 67.9%-70.4%). Among incompletely vaccinated children, 79.0% became UTD with only one additional visit, of which 63.5% required only one vaccination. With that visit, UTD coverage increased 24 percentage points to 93.5% (95% CI, 92.8%-94.2%). Coverage increased significantly within each racial/ethnic group: non-Hispanic whites, 71.7% to 94.6%; non-Hispanic blacks, 62.9% to 92.2%; and Hispanics, 66.8% to 92.1%. All but 5 states and the District of Columbia achieved >90% simulated UTD coverage. For the 4:3:1:3:3:1:4 series, baseline UTD coverage was 35.1% (95% CI, 33.8%-36.3%). Among incompletely vaccinated children, 88.4% became UTD with only one additional visit, of which 68.2% required only one vaccination. For this series, the simulated visit increased UTD coverage 57 percentage points to 92.5% (95% CI, 91.7%-93.2%). Again, coverage increased significantly within each racial/ethnic group: non-Hispanic whites, 37.8% to 93.8%; non-Hispanic blacks, 28.9% to 90.4%; and Hispanics, 31.1% to 91.2%. Although still statistically significant, differences in final coverage levels among racial/ethnic groups, for both vaccination series, are minimal.

CONCLUSION:
Achieving ≥90% coverage appears attainable, regardless of race/ethnicity, with a single additional provider visit for catch-up vaccinations among incompletely vaccinated 24-month olds. Most such children would require only one vaccination. Strategies to promote such a catch-up vaccination visit should be developed.

LEARNING OBJECTIVES:
(1) Understand the potential importance of one additional provider catch-up vaccination visit for incompletely vaccinated 24-month olds in reaching Healthy People 2010 childhood vaccination objectives; (2) Understand the potential effects of one additional provider catch-up vaccination visit on racial/ethnic disparities in vaccination coverage; (3) Understand the value of using the National Immunization Survey in assessing the potential effects of vaccination initiatives.