[Coverage, mapping and barriers to complete vaccination for age among children under 5 years in 2021: case of Adjara-Hounvè and Ahouicodji villages in southern Benin].

Background: Vaccination is a protective measure against infectious diseases and remains one of the best investments in public health. Some African countries are still struggling to reach the required child immunization coverage. Several factors are responsible for limiting immunization coverage. Most of the factors considered to limit immunization coverage are related to the health system. In addition, inaccessibility to care, especially during the critical period of the Covid-19 pandemic, greatly reduced vaccination coverage rates. In Benin, several vaccines are included in the Expanded Programme on Immunization or are administered as part of routine immunization. However, cases of non-compliance with the vaccine and persistent flaccid paralysis are still recorded in the commune of Ouidah in southern Benin. The aim of this study was to investigate the coverage and factors associated with full immunization for age in children aged 0-5 years.

Methods: A cross-sectional survey was conducted from August to October 2021 in two villages (Adjara-Hounvè and Ahouicodji) in southern Benin. All the households were included. The survey regarded children under 5 for whom a vaccination record was presented. A couple child/mother was recruited after informed consent of the mother and her child. An univariate analysis followed by a multivariate analysis was performed by using a logistic regression model to identify the variables that influence vaccine completeness. Spatial description of vaccine completeness was performed using the kriging method using ArcGIS 10.8 mapping software. Results. Of the 414 mothers surveyed, 57.49% had an immunization card, from which information was collected. Of the 238 children recruited, 141 were in Adjara-Hounvè and 97 in Ahouicodji. Of the 238 children with an immunization card, 20.6% were fully immunized for their age. All children received Baccille Calmette Guérin vaccine at birth. Since poliomyelitis, pentavalent, pneumococcal conjugate, and rotavirus are three-dose vaccines, the percentage of children who received these vaccines decreased as the number of doses increased: 96.6%, 88.2%, 78.1% and 72.3% for the four doses of polio respectively. According to 53.4% of the respondents the reception at the vaccination site was poor, and according to 70.3% of them waiting time for vaccination sessions was long. Several reasons justified the absence of complete vaccination for the age of the children: vaccination site too far from the place of residence (59.54%), lack of financial means (29.78%) and the mother's ignorance (12.76%). Education level "primary" vs "none" (ORa = 3.32; CI95% 1.07-10.25), occupation "health staff" vs "housewife" (ORa = 21.18; CI95% 3.07-145.94), mothers' knowledge of Expanded Programme on Immunization diseases (ORa = 2, 20; CI95% 1.03-4.68) and children's age 0-2 months vs ≥ 16 months (ORa = 8.53; CI95% 2.52-28.85) and 9-15 months vs ≥ 16 months (ORa = 2.99; CI95% 1.24-7.23) increased complete immunization status for age. The homogeneity of behaviour related to age-complete immunization coverage in children under 5 years was evident at mapping.

Conclusion: Age-complete immunization coverage in children under 5 years of age is very low, with a spatial homogeneity in community immunization uptake behaviour. Age-complete immunization coverage is an innovative indicator that can contribute to achieving age-specific immunization targets.