The coronavirus disease 2019 (COVID-19) pandemic has demonstrated the critical importance and persistent challenges of rapidly sharing public health and scientific information, biological samples, and genetic sequence data (GSD). Sharing these resources is crucial to characterizing the causative agent, understanding its spread, and developing diagnostics, antiviral treatments, and vaccines. But even though these resources are critical for the global health community, there is currently no legal obligation for countries to share physical pathogen samples or associated GSD. To date, researchers have often shared such resources in a spirit of scientific openness. Yet ongoing scientific cooperation has been insufficient (1) despite the scale of the pandemic threat. The lack of a clear legal obligation to share pathogens or associated GSD during a health emergency represents a blind spot in international law and governance, impeding pandemic response and scientific progress. We examine the sharing of public health information, biological samples, and GSD in the still early days of the COVID-19 pandemic, identify barriers to sharing under the current international legal system, and propose legal and policy reforms needed to enhance international scientific cooperation.