Result of a strategy using reminders before and after date of vaccination to improve timeliness of vaccination at six month

Abstract: The impact of immunization depends on timely application of the vaccines, especially relevant in children. Successful strategies for improving timeliness include the use of nominalized records and follow-up mechanisms. This study assessed the result of reminders before and after the scheduled date of vaccination to improve timely vaccination at six months. A before-and-after intervention study was performed with a time series and comparator group with 1,856 children from Villa María, Córdoba, Argentina. The strategy was implemented in the city’s public services and consisted of preparing weekly vaccination schedules, performing follow-up, and contacting and/or making active searches for no-show cases. Assessment of the result used the percentage of timely vaccination with the third dose of the pentavalent vaccine. Time series were built for each group, before and after, and were analyzed with a simple linear model. Means of the percentages were calculated with their confidence intervals, using bootstrap, and compared with the permutation method. In the intervention group, the mean percentage of timely vaccination increased significantly by 2.6 times, reaching 61.7% (56.2; 78.1). No significant increase occurred in the comparator group: p = 0.1101. The mean rates were similar before the implementation. Timely vaccination improved in children receiving the intervention. The results indicate that the proposed strategy to use nominalized records can reduce the delay in application of vaccines.