Factors associated with the circulation of vaccine-derived poliovirus (VDPV) in the province of Haut Katanga, Democratic Republic of Congo (2018-2023)

Introduction The province of Haut Katanga in the DRC experienced outbreaks of VDPV from 2018 to 2023. 90 cases were detected during this study period in 18 of the province's 27 health zones. We sought to understand the factors contributing to the emergence of this disease, which is currently being eradicated in the province. Method We conducted an analytical cross-sectional study in the 27 health zones of Haut Katanga. All cases notified during this period constituted our population. Data on confirmed cases were collected from the INRB and EPI databases. Personal patient data were collected through documentary analysis of acute flaccid paralysis case investigation forms and health centers registers. Environmental data were obtained using a survey on a form deployed in Kobocollect. Controls were selected by reasoned choice based on one control for one case. Analyses of factors associated with the scale of cases and controls were carried out using conditional logistic regression. For the environmental factors at the HZ level were sought using the Generalized Linear Mixed model. Results The factors associated with VDPV were diarrhoeal disease OR 5.1356 CI [2785 - 26.950], p-value: 0.0431; Malnutrition OR 2.3172 [1.0498 - 5.1148], p-value: 0.0375. Environmental factors for the occurrence of VDPV in the health zones are as follows: Rural HZ: OR 6.340 p=0.000 95% IC [2.632-15.273], Malnutrition OR 2.301 p=0.059. 95% [1.694-5.462].VC low OPV3 OR 3.426, p=0.015 95% IC [1.274 -9.214], Diarrhoeal disease OR 18.042 p=0.000. 95% IC [3.7525-86.765], Low IPV CV OR 17956 p=0.068 95% [95695-33699], VCS OPV3 OR 29401, p=0.032 95% IC [19.6088-89.994]. River water OR 0.7494 p=0.000 95% IC [0.2898-0.7850], Measles OR 1.795 p=0.035 95% [1.557-9.449]. Conclusion Our study identified several factors associated with the emergence of VDPVs. Certain eco-epidemiological factors together may explain the occurrence of this disease. Efforts must be made to direct available resources towards the targeted health zones efficiently.