New Report Urges Action to Ensure Sustainable, Affordable Supply of Key Vaccine Adjuvants for Global Health Use

NEW YORK, Dec. 15, 2025 /PRNewswire/ -- A new report by Treatment Action Group (TAG) warns that a key ingredient in several vaccines of global health importance may face critical supply bottlenecks in the coming years unless governments, funders, and pharmaceutical companies increase market transparency, security, and competitiveness.  

From Forest to Factory: Tracing the Supply Chains for Two Modern Adjuvants of Global Health Importance — QS-21 and MPL provides a first-of-its-kind analysis of the global supply chains of QS-21 and MPL, two adjuvants used in licensed vaccines against malaria, shingles, respiratory syncytial virus, and a promising candidate vaccine for tuberculosis (TB) called M72/AS01E.  

Adjuvants are an indispensable but underappreciated part of many vaccines. Only six adjuvants are currently approved by the U.S. Food and Drug Administration, of which five are proprietary. Understanding where adjuvants come from is essential for avoiding gaps in access that undermine global and national efforts to reduce vaccine preventable illness.

The report focuses on QS-21, one of the most potent known adjuvants and a type of saponin molecule. QS-21 is produced naturally in the soapbark tree (Quillaja saponaria), also known as quillay, a species of tree that grows natively only in Chile. Droughts, fires, and uncertainties related to climate change, as well as large volumes of QS-21 required by other industries (food and beverages, cosmetics, and mining), have raised concerns about whether the supply of quillay saponins can keep up with anticipated increases in need for vaccines.

From Forest to Factory investigates this concern and finds that the supply of quillay saponins is keeping pace with current requirements for vaccine manufacturing — but that this supply chain has only a thin safety margin. The report profiles the different companies operating in the market, summarizes emerging alternative sources of quillay saponins (which do not rely on natural harvest), and estimates the total supply and demand for QS-21 and related saponins for global vaccine use over the coming years.

Currently, just one company (Desert King) is the sole supplier of quillay saponins for all approved and late-phase vaccines using them as adjuvants. Approved vaccines that contain QS-21 are made by two companies: GSK and Novavax. Additional suppliers of quillay saponins are positioned to claim some market share in the coming years, but even then, the quillay market will remain an oligopoly with limited competition among a small number of producers.

"We found that monopolies exist up and down the supply chain, which creates inherent vulnerabilities in assuring sustainable, affordable access," commented Mike Frick, TB project co-director at TAG. "The reliance on a few pivotal players means that any unexpected development — climate shocks, trade wars, business exits — could rapidly escalate into supply disruptions that impede vaccine access. We need coordinated action by governments, industry, and philanthropic partners to shore up a predictable, sustainable, and affordable supply of quillay saponins for lifesaving vaccine use."

The report puts forward the following recommended actions for governments:

• Increase transparency along the supply chain by monitoring manufacturing capacity, market concentration, and potential supply threats or disruptions;
• Ensure a competitive market by encouraging supply diversification and discouraging anticompetitive business practices;
• Invest in improvements for producing quillay-derived adjuvants including aeroponics, production in cell culture, or [semi]synthetic production methods; and
• Remove barriers to adjuvant research and manufacturing by supporting open, collaborative adjuvant development.

A final recommendation calls attention to the provenance of QS-21 in Indigenous traditional knowledge and explores whether legal frameworks governing use of genetic resources might apply to quillay saponins. "The Mapuche people have recognized the tremendous medicinal properties of the soapbark tree for centuries. Our feeling is that regardless of whether there is a requirement under the Convention on Biological Diversity or Chilean law, there is a compelling moral case for establishing access and benefit sharing for QS-21, a framework that recognizes the Mapuche and values quillay as a resource to be shared, managed, and conserved for the benefit of all of humanity," said TAG executive director Mark Harrington.

View the report here: https://www.treatmentactiongroup.org/publication/from-forest-to-factory-tracing-the-supply-chains-for-two-modern-adjuvants-of-global-health-importance-qs-21-and-mpl

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About TAG: Treatment Action Group (TAG) is an independent, activist and community-based research and policy think tank fighting for better treatment, prevention, a vaccine, and a cure for HIV, tuberculosis, and hepatitis C virus. TAG works to ensure that all people with HIV, TB, and HCV receive life-saving treatment, care, and information. We are science-based treatment activists working to expand and accelerate vital research and effective community engagement with research and policy institutions. Learn more at treatmentactiongroup.org.

SOURCE Treatment Action Group