Comparative estimates of crude coverage of the Mexican immunization program: Findings from a national survey

The purpose of the study is to provide estimates for immunization coverage, considering single-dose and schemes (three or five vaccines), by comparing self-report method to immunization cards, while also assessing the timeliness of immunization in Mexico, with reference to Mexican Immunization Program guidelines. Data on immunization was obtained from the Mexican Immunization Survey conducted in 2017 that aimed to assess crude (card-based) coverage at the regional level. Timely immunization was defined with reference to National Immunization Program guidelines, and immunization coverage was defined as a three or five vaccine scheme, based on previous national reports of immunization coverage. Immunization coverage estimates account for sample weights from the complex survey design. We used weighted immunization coverage estimates to assess the extent to which immunization cards and self-reporting concurred. It was found that most Mexican children are not receiving their full vaccine schedule in a timely manner. Concerning children under twelve months of age, the coverage targets for National Immunization of 95 % was not reached for either vaccine, and only 2.94 % (95 % CI 0.92-9.01) who had been receiving a three-vaccine scheme were considered as fully immunized in a timely manner. In contrast, coverage increased to 33.94 % (95 % CI 26.99-41.66), when untimely immunizations were taken into account, and the 95 % target was reached for five vaccines. Likewise, there is little correlation between self-report and immunization cards but rates show more concurrence, when only considering the proportion of true positives. In conclusion it was find that children at a local level are vaccinated in an incomplete and untimely manner. In order to improve immunization systems, a nominal registry of administered doses is thus of paramount importance. There is a need to address underlying health inequalities, as well as the factors associated with these, resulting in improved chances of a disease-free childhood and healthy life.