2025 Spotlight: Reflections on Outbreak Response and Generating Meaningful Data

As I look back at 2025, one defining moment came when Ethiopia’s Ministry of Health contacted Sabin Vaccine Institute for support as the country confronted its first-ever Marburg outbreak. While it was Ethiopia’s first Marburg outbreak, it was not new for us. Having responded to a Marburg outbreak in Rwanda the year before, the Sabin team moved quickly — building on established partnerships and lessons learned to support the national response, while generating evidence to support the development of our investigational cAd3-Marburg vaccine.

Marburg virus disease is rare but devastating, with case fatality rates that can exceed 80 percent. After an incubation period, which can vary from 2 to 21 days, symptoms appear suddenly, and patients can deteriorate within days — progressing to organ failure, shock, and death. Once an outbreak is detected, speed is not optional; urgent action can mean the difference between containment and catastrophe.

Responding with Speed, Science, and Partnership

In both Rwanda and Ethiopia, Sabin acted at the request of national governments to deploy our investigational cAd3-Marburg vaccine. There are no licensed vaccines for Marburg virus disease. Sabin’s investigational vaccine was administered under a Phase 2, rapid-response clinical trial after the protocols were reviewed and approved by national regulatory and ethical authorities.

The objective was consistent across both countries:

• Support national outbreak response efforts, including protection of high-risk frontline workers
• Generate critical data to advance vaccine development of our cAd3-Marburg vaccine

Close coordination with ministries of health and global partners ensured that vaccine R&D priorities aligned with national response plans. Our partners at REITHERA, IQVIA, and CEPI (Coalition for Epidemic Preparedness Innovations) added critical manufacturing, operational, and technical capacity. The Biomedical Advanced Research and Development Authority (BARDA), part of U.S. Department of Health and Human Services’ Administration for Strategic Preparedness and Response (ASPR) and funder of the cAd3-Marburg vaccine development, moved with urgency to authorize vaccine delivery — demonstrating the importance of standing public-sector partnerships when time is measured in days, not months.

What Was Different — and Why It Mattered

Rwanda marked the first-ever deployment of Sabin’s cAd3-Marburg vaccine during an active outbreak. This required building systems in real time — protocol design, regulatory and ethical approvals, logistics, and clinical trial operations — under intense conditions. While challenging, the Rwanda response proved a critical point: investigational vaccines can be deployed safely and effectively during outbreaks to address public health concerns and generate needed clinical data.

Rwanda’s preparedness made a measurable difference. After participating in CEPI’s 100 Days Mission, a preparedness exercise conducted with CEPI and IQVIA just weeks before the outbreak, the country was already familiar with outbreak response roles, decision-making processes, and coordination mechanisms. That preparation, combined with strong working relationships, gave the response a significant operational advantage.

Our work with Ethiopia, in turn, benefited directly from what we learned in Rwanda. But the context was markedly different. Ethiopia’s outbreak occurred in the southern regions, including in some remote areas, rather than an urban center like Kigali. The country is more than 40 times larger geographically and nearly 10 times more populous than Rwanda, making logistics and contact tracing more complex. While eligible clinical trial participants in Kigali were substantial and concentrated, Ethiopia’s were smaller and more dispersed. Ethiopia’s clinical trial also included a randomized cohort.

Each context demanded adaptation and reinforced that no two outbreaks are the same.

What We Learned: Trust Is Key

Perhaps the most important lesson from our work in outbreak response is that trust and open communication are as critical as vaccines.

In Rwanda, we learned the value of bringing core decision-makers together — Sabin, ministries of health and other national decision-makers, CEPI, IQVIA, and BARDA — around daily, open, and transparent communication. Those daily calls became the backbone of the response, enabling rapid problem-solving and shared decision-making. With agreement from our Ethiopian colleagues, we replicated that model, with daily coordination calls to align on strategy, address operational challenges, and adjust in real time.

At the center of these calls were the Rwandan and Ethiopian research institutions, Rwanda Biomedical Centre and Armauer Hansen Research Institute, that sponsored or oversaw clinical trial protocol design, regulatory and ethical approvals, and implementation. These research institutions, as well as others in the governments, communicated directly with each other to share learnings and concerns. The trust built in Rwanda — and our partners’ endorsement of Sabin — helped establish credibility and confidence with Ethiopian counterparts from the outset.

Preparedness is not just plans and protocols. It is relationships built before a crisis begins.

Why Marburg Vaccine Development Matters

Unlike COVID-19, there is no commercial market for a Marburg vaccine. Demand is limited to outbreak response, health workers, and emergency stockpiles. Progress depends almost entirely on public sector and philanthropic investment. Sabin’s role is to ensure that lack of commercial viability does not translate into lack of protection.

As I approach my 10-year mark at Sabin, this feels like a full-circle moment for me. Early in my tenure, we made a deliberate decision to develop vaccine candidates for some of the world’s deadliest diseases — threats we knew urgently needed solutions, even though there was little or no viable commercial market to drive investment.

In the years that followed, we have advanced vaccines for the high-consequence pathogens Sudan virus, a form of ebolavirus, and Marburg virus to Phase 2 clinical trials — often working hand in hand with national governments and global health partners. Our focus remains clear and constant: diseases that disproportionately affect the most vulnerable communities and are too often overlooked by commercial developers.

Looking Ahead

Disease outbreaks are expected to become more frequent as multiple global trends are converging to increase both the risk of spillovers and the speed of spread. Climate change is altering ecosystems and expanding the range of disease-carrying animals and vectors, while global travel and dense urban populations allow outbreaks to spread more rapidly. Continued research, including during outbreak responses, is necessary to protect everyone, everywhere.

The experiences in Rwanda and Ethiopia strengthened our operational playbook, deepened partnerships, and reinforced the value of sustained investment in vaccine R&D and outbreak preparedness. Thanks to what we learned this year, we are better prepared to meet them —faster, smarter, and together.