This indicator measures the percentage of children (typically aged 12–23 months) who have received three doses of the pentavalent (Penta 3) vaccine, which protects against diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b, over a ten-year period. Completion of the Penta 3 vaccine series serves as a key marker for full routine immunization coverage and consistent access to child vaccination services. Monitoring Penta 3 coverage rates over 10-year periods helps evaluate the long-term performance of national immunization programs, identify persistent geographic and socioeconomic disparities in vaccine access, guide strategies for outreach, cold chain strengthening, and vaccine supply management, assess progress toward herd immunity and disease elimination targets, and measure the effectiveness of interventions aimed at reducing vaccine-preventable childhood morbidity and mortality.