Announcing the Strep A Vaccine Fund
Most people in wealthy countries know Strep A as the cause of strep throat, an uncomfortable but easily treated childhood illness. But globally, Strep A is responsible for an estimated 639,000 deaths per year. That death toll rivals those of HIV/AIDS and malaria, but Strep A receives dramatically lower levels of funding and public attention.
Given the scale and neglect of this burden, we see a coordinated vaccine effort as one of the highest-impact opportunities in global health philanthropy. Today, we’re launching the Strep A Vaccine Fund: a multi-donor initiative to accelerate the development of Strep A vaccines.
Strep A (Streptococcus pyogenes) is responsible for hundreds of millions of cases of strep throat and skin infections each year, as well as scarlet fever and rarer but serious invasive conditions like sepsis and necrotizing fasciitis. Its most consequential effect, however, is rheumatic heart disease (RHD), a chronic condition that occurs when the body’s immune response to repeated Strep A infections misfires and damages the heart valves. Today, roughly 55 million people live with rheumatic heart disease, many of them young and in low- and middle-income countries or disadvantaged communities within rich countries. Without access to monthly penicillin injections or heart valve surgery — both of which are largely unavailable in the regions where the disease is most common — advanced RHD is often fatal.
The Strep A Vaccine Fund builds on the model of our other multi-donor funds, including the Lead Exposure Action Fund and the Abundance & Growth Fund, and reflects our increasing focus on partnering with new donors to tackle important global problems. We aim to mobilize $200 million over the fund’s five-year life, and are off to a strong start with just over $140 million raised at launch. This post explains why we think developing a vaccine for Strep A is so important and what the fund seeks to achieve.
Why Strep A?
In more than a decade of evaluating causes, we’ve rarely seen a problem this neglected and tractable relative to its scale:
- The harm is enormous. A century ago, the American Heart Association was established largely to address rheumatic fever (the immune reaction to Strep A that can lead to RHD), which was later dubbed “childhood’s greatest enemy.” Back then, rheumatic fever and RHD were a leading cause of death among American children. Thanks to improved living conditions and healthcare, RHD has since been virtually eliminated in wealthy countries, but remains a major killer of young people in low and middle-income countries. In fact, the estimated 639,000 annual deaths from Strep A diseases likely understate the true toll, given data gaps in the most affected regions of sub-Saharan Africa and South Asia. And beyond mortality, RHD causes years of illness and disability.
- The neglect is striking. Strep A and RHD are chronically underfunded. It’s difficult to get exact figures, but Impact Global Health estimated the average annual R&D funding for rheumatic fever between 2019 and 2023 was around $14 million, roughly $1–2 per disability-adjusted life year (DALY). To put that in perspective, malaria and TB — themselves neglected challenges that we fund — received around 50 times the research funding of Strep A.
- The problem looks tractable. There are strong reasons to believe it is possible to interrupt the development of RHD by reducing exposure to Strep A infections, as we have seen in the US. There are also reasons to believe a Strep A vaccine is achievable. Efforts to vaccinate against Strep A date back over a century, and even early attempts showed signs of protection. Today, multiple modern vaccine candidates are in development, and some are ready for human trials. Recent scientific advances, including innovative new trial designs have opened up possibilities for faster, more efficient clinical testing, and new vaccinology techniques provide a route to improved vaccine design.
Some of the biggest obstacles in the field to date appear to have been financial — and therefore, ones we can help address. For example, StreptinCor first showed promise in animal studies 15 years ago, and Combo4 from GSK demonstrated preclinical proof of concept over six years ago — but both have only just entered clinical trials.
That said, success is never guaranteed, and tractability is where we still have the biggest questions: we don’t know if the existing candidates will work, and it’s not yet clear what data regulators will require. Additionally, commercial vaccine developers have been slow to invest, despite a potential market in high-income countries. But we’ve surveyed the scientific landscape here extensively and believe that a vaccine for Strep A looks more tractable than vaccines for more complex diseases like TB, malaria, or HIV.
Our approach
The Strep A Vaccine Fund will support work spanning the vaccine development pathway, from early science through to preparing for licensure. Our strategy will cover five broad areas:
- Accelerating existing vaccine candidates through trials. Around 20 Strep A vaccine candidates have been developed over the past two decades, but progress to clinical trials has been slow: only four candidates have been tested in humans, and none have completed an efficacy trial. We are funding the work needed to move some of the most promising candidates forward, including through Strep A pharyngitis human challenge trials, where vaccinated volunteers are deliberately exposed to Strep A in a controlled setting to generate early proof-of-concept efficacy signals, and improve our understanding of what types of vaccines may or may not work. We have already funded early-stage development of two candidates in the pipeline and plan to support multiple in parallel to increase the chances of success.
- Improving scientific foundations. Strep A vaccine development has been held back by gaps in the underlying science, with animal models and assays that poorly replicate the human diseases we’re trying to prevent. There are also open questions about when and how children in high-burden settings acquire Strep A infections, which is important for informing the timing and durability of vaccination. We’re interested in funding work to develop better assays and preclinical models, to expand human challenge models to include Strep A skin infections, and to build a clearer picture of Strep A and RHD in early childhood.
- Seeding the next-generation of vaccines. Because the field has been so underfunded, most current candidates were designed years ago, before the most recent advances in antigen discovery and vaccinology. Alongside the existing pipeline, we are investing in newer approaches, including methods for identifying important antigens, improved immunogen design, alternative delivery platforms, and novel adjuvants that could produce vaccines that are more effective, cheaper to manufacture, and easier to deliver at scale.
- Preparing the path to deployment. A vaccine only saves lives if it reaches the people who need it, and previous experience has taught us that waiting until the end of clinical development to prepare for approval and implementation can delay rollout by years. We are funding early engagement with regulators and policymakers so that when a vaccine succeeds in trials, the pathway to approval and delivery is clearer. We’re also supporting work to establish acceptable clinical trial endpoints — such as early RHD detected by echocardiography — that could substantially shorten the path to pivotal efficacy data. We are also investing in better burden-of-disease data to help governments and funders see the scale of the problem in their own countries, and funding organizations like REACH to provide technical assistance to governments designing national RHD prevention programs.
- Strengthening coordination in the Strep A vaccine community. A more connected community will learn faster and be in a stronger position to accelerate vaccine development for the field as a whole, not just any single candidate. Without active coordination, developers tend to work in silos with limited alignment on trial design or endpoints, making progress slower and less even across the pipeline. Coordination across developers, regulators, and policymakers on trial endpoints and assays would allow candidates to be meaningfully compared and improve decision-making across the field. We have supported this kind of infrastructure-building since before the fund’s launch, including through our co-funding of the Strep A Vaccine Global Consortium (SAVAC). Building on that work, we made a recent grant to Bridges to Development to deliver the first global conference on Strep A vaccine development, expected in 2027. Over time, we expect to fund further work to strengthen the community infrastructure needed to accelerate vaccine development.
At a recent conference, former U.S. Surgeon General Jerome Adams noted striking parallels between our approach and Operation Warp Speed. That’s not a coincidence. While we can’t replicate that ~$18 billion program, the Warp Speed model proved that the biggest delays in vaccine development are often not scientific but structural and financial, and we think its lessons can be successfully applied to many other scientific challenges, including a vaccine for Strep A. We are applying much of its core logic: run things in parallel, back a diverse portfolio of candidates, and prepare for each stage well in advance.
Beyond vaccines
Our primary focus is vaccine development, but given its long timeline, we’re also investing in the most credible near-term approaches to reducing RHD.
For example, we made an $11 million grant to the ADUNU project in Uganda, which uses portable ultrasound technology to screen for early-stage RHD and link patients to monthly antibiotic treatment that can halt disease progression. The team has already screened roughly 30,000 people and achieved a 76% treatment adherence rate — a strong result for a program requiring monthly injections in a resource-constrained setting.
We also co-funded the GOAL-Stop trial, testing whether two years of antibiotic treatment is sufficient to prevent early RHD from worsening, compared to the current guideline of approximately ten years. If confirmed, this finding could prompt revised WHF and WHO guidance and make screening programs far easier to establish at scale.
Why now
We believe this is an unusually important moment for Strep A. Despite the dearth of funding, the community has made important progress. The scientific landscape is now stronger than ever, with multiple candidates approaching clinical trials and new tools like the human challenge model and portable ultrasound technology to detect early-stage RHD, opening up faster paths to efficacy data. At the same time, institutions that have traditionally led global health R&D are under growing pressure, and funding gaps for neglected diseases are widening. This is an unusually good moment for philanthropy to make a difference.
Strep A has been overlooked for more than a century despite a health burden that rivals much better-known diseases, and the small, dedicated community of researchers and advocates who have been pushing the field forward for decades have done so on very limited budgets. We’re launching the Strep A Vaccine Fund to bolster the resources and coordination behind that work, and to compress timelines that would otherwise stretch out multiple decades. By the end of 2030, we want the field to have doubled the number of vaccine candidates in clinical trials, and have at least one ready for Phase 3 trials, with a clearer path to licensure.
We are grateful to Adam and Abigail Winkel, Good Ventures, Lucinda Southworth, Patchwork Collective, and other anchor funders for their partnership. If you are interested in learning more or joining the fund as a donor, please reach out. To learn more about our grantmaking, please visit our fund page.