BACKGROUND:

India has the highest number of deaths among children younger than 5 years of age globally; the majority are from vaccine preventable diseases. Untimely vaccination unnecessarily prolongs susceptibility to disease and contributes to the burden of childhood morbidity and mortality yet there is scarce literature on vaccination delays. The aim of this study is to characterize the timeliness of childhood vaccinations administered under India\'s routine immunization program using a novel application of an existing statistical methodology.

METHODS:

This study utilized the District Level Household and Facility Survey Data, 2008 from India using vaccination data from children with and without immunization cards. Turnbull estimator of the cumulative distribution function was used to estimate the probability of vaccination at each age. Timeliness of Bacille Calmette-Guerin (BCG), all three doses of diphtheria, pertussis, and tetanus vaccine (DPT), and measles-containing vaccine (MCV) were considered for this analysis.

FINDINGS:

Vaccination data on 268,553 children who were 0 to 60 months of age were analyzed; timely administration of BCG, DPT3 and MCV occurred in 31%, 19%, and 34% of children, respectively. The estimated vaccination probability plateaued for DPT and BCG around the age of 24 months, whereas MCV uptake increased another 5% after 24 months of age. The five year coverage of BCG, DPT3, and MCV in Indian children was 87%, 63%, and 76%, respectively.

INTERPRETATION:

Lack of timely administration of key childhood vaccines, especially DPT3 and MCV, remains a major challenge in India and likely contributes to the significant burden of VPD-related morbidity and mortality in children.