During the period July-December 2023, JSI, as the global learning partner, continued to provide technical assistance and collaborate and co-create with the four Country Learning Hubs (CLHs). This semiannual update for the Gavi Board and other stakeholders highlights the ZDLH consortium’s efforts to leverage evidence for a deeper understanding of the factors that affect the implementation and performance of strategies to identify and reach ZD and under-immunized (UI) children and missed communities. It synthesizes findings, challenges, and recommendations across the IRMMA framework emerging from the Learning Hubs.