Reference materials are critical in assay development for calibrating and assessing their suitability. The devasting nature of the COVID-19 pandemic and subsequent proliferation of vaccine platforms and technologies has meant that there is even a greater need for standards for immunoassay development, which are critical to assess and compare vaccines’ responses. Equally important are the standards needed to control the vaccine manufacturing processes. Standardized vaccine characterization assays throughout process development are essential for a successful Chemistry, Manufacturing and Controls (CMC) strategy. In this perspective paper, we advocate for reference material incorporation into assays and their calibration to International Standards from preclinical vaccine development through control testing and provide insight into why this is necessary. We also provide information on the availability of WHO international antibody standards for CEPI-priority pathogens.