R&D experts to create playbooks that map immune markers in deadly diseases

OSLO/SEATTLE, 21 JUL 2025—The global health organisations CEPI and PATH are joining forces to create pivotal playbooks that map all available research into specific immune markers that indicate protection against target viruses with epidemic or pandemic potential.

Supported by US$8 million in funding from CEPI, these research and development (R&D) manuals could hold important insights for scientists, vaccine developers and regulators to more quickly and easily determine whether a vaccine candidate will generate protective immunity against certain deadly pathogens. This includes viruses like monkeypox, Lassa, Zaire ebolavirus, Sudan ebolavirus, and Marburg. 

The immune response protects the body against an infectious disease with antibodies, B cells, T cells, neutrophils and/or killer cells. Specific immune markers that signal protection against infection or disease and may reliably predict the level of a vaccine’s effectiveness are known as correlates of protection (CoP). CoPs have been used to advance the approval of vaccine candidates when large-scale efficacy trials are not possible because there are too few cases of a disease or because outbreaks are too explosive or sporadic.

While there is a growing body of research identifying potential immune markers for different epidemic diseases, scientists lack alignment when it comes to the tools and approaches used to measure these markers, making it difficult to compare findings and define or discover a CoP.

“Immune markers are one of the holy grails in the vaccine field, acting as a biological gauge to infer whether a vaccine candidate provides sufficient immunity and can advance to later testing or regulatory approvals,” explains Dr Kent Kester, Executive Director of Vaccine R&D, CEPI. “However, little is known about what biomarker equates to protection for some CEPI priority pathogens leaving developers somewhat in the dark. These playbooks could help us to more rapidly prepare and prioritise vaccines with promising immune profiles even before a virus hits, supporting CEPI’s goal to develop vaccines against outbreaks in as little as 100 days.”

The playbooks will consolidate current knowledge of the immune markers for specific diseases, providing guidance to accelerate vaccine R&D and support licensure. More streamlined and easily accessible information on a CoP associated with an outbreak disease could aid regulators and offer a potential alternative pathway for vaccine licensure. Gaps in our scientific understanding on immune markers that could impact the ability to respond to an outbreak in a timely way will be highlighted to allow funders and researchers to better target their efforts. 

“PATH is pleased to partner with CEPI and contribute our scientific and technical expertise to better understanding potential correlates of protection for several priority viruses of outbreak and epidemic potential,” says Jessica Milman, Global Head of the Center for Vaccine Innovation and Access at PATH. “These playbooks will provide invaluable information to help guide swift decision-making in an emergent situation and ultimately accelerate vaccine development for these priority pathogens.”

The first playbook will be published online within a year under open access to ensure the entire R&D community benefits from the data.