Antimicrobial resistance (AMR) is a critical global health threat, with an estimated 1.27 million deaths annually attributed to antibiotic-resistant bacterial infections. Streptococcus pneumoniae remains a leading cause of morbidity and mortality in children under five, particularly in low- and middle-income countries. While pneumococcal conjugate vaccines (PCVs) have substantially reduced invasive pneumococcal disease incidence, their impact on the transmission dynamics of antibiotic-resistant strains remains poorly understood.

My doctoral research addresses this knowledge gap by leveraging whole-genome sequencing data from a cluster-randomized trial of PCVs conducted in Nha Trang, Vietnam, a high-burden setting with significant challenges related to antibiotic consumption and resistance. Using advanced phylogenetic reconstruction, Bayesian phylodynamic modeling, and spatial epidemiological methods, I aim to characterize the spread of drug-resistant pneumococcal strains and quantify the vaccine's impact on resistance transmission.