Child immunization is a critical public health intervention aimed at preventing infectious diseases among children in Malawi's rural areas. A quasi-experimental design was employed to assess changes in CHW performance metrics before and after implementing the training model. Data were collected through surveys conducted among a sample of CHWs and parents/caregivers of children aged under five years, using validated questionnaires. CHWs who received training demonstrated an increase in BCG immunization coverage by 15% (95% CI: 7-24%) compared to those not trained. There was no significant change observed for DPT vaccines. The training model significantly enhanced CHW performance in delivering BCG vaccinations, leading to improved child immunization coverage rates. Continuous and periodic retraining of CHWs is recommended to maintain the high levels of BCG immunization coverage. Further research should explore the scalability and sustainability of this intervention across diverse settings. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.