Spatio-temporal patterns and vaccination effectiveness in rabies risk using surveillance data from Kaduna State, Nigeria

Abstract

Rabies remains a significant public health threat in Nigeria despite the availability of effective vaccines. Understanding spatial patterns of exposure and the protective effect of canine vaccination is essential for targeted control. We conducted a retrospective spatio-temporal analysis of routine rabies surveillance data from Kaduna State, Nigeria, covering January 2024 to March 2025. Data included animal bite incidents, vaccination status of biting animals, bite characteristics, and laboratory rabies confirmation outcomes. Temporal trends were assessed weekly and monthly. Spatial clustering was evaluated at the Local Government Area (LGA) level using Global Moran’s I, Local Indicators of Spatial Association (LISA), and Getis–Ord Gi* statistics. Vaccine effectiveness was estimated among animals with known vaccination status by comparing the risk of laboratory-confirmed rabies between vaccinated and unvaccinated animals using relative risk and multivariable logistic regression adjusting for animal sex and bite provocation. A total of 153 animal bite incidents were recorded across all 23 LGAs, with dogs accounting for 98.7% of cases. Vaccination coverage among biting animals was 69.3%, and 5.9% were laboratory-confirmed rabid. Significant spatial hotspots of rabies exposure were identified in Zaria (Gi* = 2.31, p = 0.02) and Jema’a (Gi* = 2.05, p = 0.04), while global spatial autocorrelation was not significant (Moran’s I = -0.15, p = 0.80). Rabies was confirmed in 1.9% of vaccinated animals compared with 14.9% of unvaccinated animals, corresponding to a crude vaccine effectiveness of 87.5%. After adjustment, vaccination was associated with an 88% reduction in the odds of rabies (adjusted odds ratio = 0.12; 95% CI: 0.02–0.59; p = 0.01). Canine rabies vaccination was strongly protective under routine field conditions in Kaduna State. The identification of localized spatial hotspots highlights the need for geographically targeted vaccination and strengthened surveillance to support rabies elimination efforts.