Background The natural history of latent rheumatic heart disease (RHD) detected by echocardiography remains unclear. We aimed to assess the accuracy of a simplified score based on the 2012 World Heart Federation criteria in predicting mid‐term RHD echocardiography outcomes in children from 4 different countries. Methods and Results Patient‐level baseline and follow‐up data of children with latent RHD from 4 countries (Australia, n=62; Brazil, n=197; Malawi, n=40; New Zealand, n=94) were combined. A simplified echocardiographic scoring system previously developed from Brazilian and Ugandan cohorts, consisting of 5 point‐based variables with respective weights, was applied: mitral valveanterior leaflet thickening (weight=3), excessive leaflet tip motion (3), regurgitation jet length ≥2 cm (6), aortic valve focal thickening (4), and any regurgitation (5). Unfavorable outcome was defined as worsening diagnostic category, persistent definite RHD or development/worsening of valve regurgitation/stenosis. The score model was updated using methods for recalibration. 393 patients (314 borderline, 79 definite RHD) with median follow‐up of 36 (interquartile range, 25–48) months were included. Median age was 14 (interquartile range, 11–16) years and secondary prophylaxis was prescribed to 16%. The echocardiographic score model applied to this external population showed significant association with unfavorable outcome (hazard ratio, 1.10; 95% CI, 1.04–1.16; P =0.001). Unfavorable outcome rates in low (≤5 points), intermediate (6–9), and high‐risk (≥10) children at 3‐year follow‐up were 14.3%, 20.8%, and 38.5% respectively ( P <0.001). The updated score model showed good performance in predicting unfavorable outcome. Conclusions The echocardiographic score model for predicting RHD outcome was updated and validated for different latent RHD populations. It has potential utility in the clinical and screening setting for risk stratification of latent RHD.