Immunization plays a crucial role in global health security, preventing public health emergencies of international concern and protecting individuals from infectious disease outbreaks, yet these critical public health benefits are dependent on immunization law. Where public health law has become central to preventing, detecting, and responding to infectious disease, public health law reform is seen as necessary to implement the Global Health Security Agenda (GHSA). This article examines national immunization laws as a basis to implement the GHSA and promote the public's health, analyzing the scope and content of these laws to prevent infectious disease across Sub-Saharan Africa. Undertaking policy surveillance of national immunization laws in 20 Sub-Saharan African countries, this study: (1) developed a legal framework to map the legal attributes relevant to immunization; (2) created an assessment tool to determine the presence of these attributes under national immunization law; and (3) applied this assessment tool to code national legal landscapes. An analysis of these coded laws highlights legal attributes that govern vaccine requirements, supply chains, vaccine administration standards, and medicines quality and manufacturer liability. Based upon this international policy surveillance, it will be crucial to undertake legal epidemiology research across countries, examining the influence of immunization law on vaccination rates and disease outbreaks.