A multi-level analysis of the characteristics of zero-dose and under-vaccinated populations in low and middle-income countries Seminar

Achieving equity in immunization coverage has been a topical issue within the global health community. Despite increased efforts in this regard in recent times, certain populations still remain un- or under-vaccinated in many low- and middle-income countries (LMICs). These populations are often thought to reside in remote-rural areas, urban slums and conflict areas. In this talk, I will present our recent work investigating the effect of these community-level factors, alongside a wide range of other individual and household level covariate factors, on immunization coverage.

Our study focused on nine LMICs, for which we obtained household survey data from their most recent Demographic and Health Survey and other relevant geospatial data. We undertook preliminary analyses of the data and then fitted Bayesian multi-level regression models to determine community-level and other covariate factors significantly associated with non-vaccination, using the receipt of the first dose of diphtheria-tetanus-pertussis (DTP1) vaccine and the first dose of measles-containing (MCV1) vaccine, and those significantly associated with under-vaccination using the receipt of all three recommended DTP doses (DTP3).

We found that, compared to other covariate factors, the three community-level factors were less frequent significant determinants of the receipt of DTP1/DTP3/MCV1, and the directions of the estimated odds varied - particularly with living in conflict and slum areas. Travel time was a more frequent determinant of under-vaccination compared to non-vaccination. Other factors such as maternal utilization of health services (skilled birth attendance, antenatal care attendance, maternal receipt of tetanus toxoid vaccination and postnatal care), maternal education and ethnicity were each significant determinants of the receipt of DTP1/DTP3/MCV1 in more than half of the study countries in which they were measured. In the same manner, the receipt of both routine vaccine doses (DTP1 and DTP3) varied significantly by region, while the receipt of MCV1, for which campaigns are also conducted, had significant associations with access to a health intervention (ownership of a mosquito bednet) and period of birth. Our findings demonstrate the need for a broader, multi-faceted approach to tackling inequities in vaccination coverage in LMICs.

Speaker Information

Dr Chigozie Edson Utazi - Senior Research Fellow within Geography and Environmental Science at the University of Southampton.