Refresher training in administering intradermal BCG-vaccine increased BCG-scarring rates in rural Guinea-Bissau

Background: A correct vaccination technique is important for developing BCG scars. Having a BCG scar is associated with lower mortality among BCG-vaccinated children. Aim: To compare BCG-scar prevalences among children vaccinated before and after refresher training in BCG vaccination technique. Methods: BCG-scar prevalence is assessed through a health and demographic surveillance system in rural Guinea-Bissau. In the context of a randomised trial, staff at health facilities in three regions (intervention area) received refresher training on BCG vaccination technique. In a fourth region (control area) no training was implemented. In logistic regression models, we compared scar prevalence among children vaccinated before and after the training. Results: BCG-scar prevalence increased from 75 % to 92 % (odds ratio (OR) = 4.19, 95 %CI 2.92–6.01) in the intervention area and from 71 % to 78 % (OR = 1.43, 95 %CI 0.89–2.29) in the control area (p-value for same increase: <0.001). Conclusion: BCG scarring rates increased after training in vaccination technique.