Serological response to field rabies vaccination in owned dogs in the immune belt of Peninsular Malaysia.

Rabies vaccination is conducted along the northern border of Peninsular Malaysia, but paired field serological data are limited. We analysed routine programme data from 154 owned dogs sampled immediately before vaccination and 30-83 days later (median, 43 days). Rabies virus-neutralising antibody levels were measured using the fluorescent antibody virus neutralisation test. Paired levels in IU/mL were compared using the Wilcoxon signed-rank test, and benchmark proportions were compared using the exact McNemar test. The proportion with levels ≥ 0.5 IU/mL increased from 72.7% (112/154; 95% confidence interval [CI], 65.2-79.1%) to 98.1% (151/154; 95% CI, 94.4-99.3%; p < 0.001). Three dogs remained below the benchmark. Median levels increased from 1.98 IU/mL (interquartile range [IQR], 0.38-5.92) to 13.5 IU/mL (IQR, 4.5-13.5); the median paired increase was 5.45 IU/mL (bootstrap 95% CI, 3.31-7.25; p < 0.001). Levels increased in 128 dogs, were unchanged in 19 and decreased in seven. Eighty follow-up values equalled the dataset maximum of 13.5 IU/mL, suggesting possible upper-end censoring. Vaccination history identified 99 previously vaccinated dogs and seven recorded as receiving their first vaccination, limiting comparison of these groups. Nearly all dogs retained at follow-up met the serological benchmark. Convenience sampling, incomplete follow-up and uncertain measurement limits restrict inference to this cohort and preclude estimates of population immunity or clinical effectiveness.