Leading with Science and Evidence in a Time of Retreat

This World Health Day, the World Health Organization (WHO) urges the world to stand with science. With the theme “Together for health. Stand with science,” the campaign calls for embracing evidence, supporting science-led solutions, and advancing global cooperation to turn evidence into action.

This call to action comes as evidence-based systems and global health security commitments are being dismantled at an alarming pace. As global resources become more constrained, evidence-based tools that guide investments toward maximum impact are more important than ever.

Dismantling Health Security Systems

The United States has rescinded more than $500 million in federal contracts for mRNA vaccine research and development, undermining a technology central to the next generation of vaccines for emerging outbreaks, including zoonotic diseases such as dengue and Zika viruses. These cuts weaken capacities to protect against biological threats.

The toll on global health systems over the last year has been far-reaching. In 2025, approximately 86% of USAID financial awards were terminated, including funds essential to saving lives internationally. The slashing of U.S. foreign assistance was followed by official development assistance (ODA) cuts by the United Kingdom, Germany, Canada and other nations, compounding the impact on global health security. If current funding trends continue, global aid cuts could lead to 9.4 million or more additional deaths by 2030.

A Renewed Focus on One Health 

As World Health Day emphasizes leading with science, the WHO is prioritizing a One Health approach. One Health is the idea that human health cannot be separated from the animals, ecosystems, and environments around us. Most emerging infectious diseases originate at the interface between humans, animals, and the environments they share, making cross-sectoral, evidence-driven responses essential to effective health security.

Many African health institutions have already embedded One Health as a continental priority. In 2018, Africa CDC established a transdisciplinary One Health approach for its five technical divisions: surveillance and disease intelligence, emergency preparedness and response, laboratory systems, public health institutes and research, and disease control programs. In 2022, the African Union established a One Health Coordinating Group on Zoonotic Diseases to strengthen cross-border surveillance and coordination among member states.

This investment in One Health is grounded in the realities of Africa’s disease landscape. Nearly 60% of emerging infectious diseases and 75% of new human pathogens detected over the last three decades have originated from animals. Africa faces a growing risk of zoonotic outbreaks, and climate change is compounding this risk: shifting rainfall patterns, habitat disruption, and rising temperatures are expanding the range of disease vectors and pushing wildlife, livestock, and human populations into closer contact. Biological threats are accelerating across the continent at a moment when the funding necessary to address them is being pulled back.

Evidence‑Driven Decisions for a Safer Future

Filling the gaps left by ODA cuts will require efficient and equitable use of resources, ensuring that all investments align with national health agendas. The Africa Health Security (AHS) Index will provide the country-level data to do exactly that.

Created on the recommendation of African public health leaders, the AHS Index will provide new data on health security targets across the continent, including new preparedness indicators at the intersection of health and climate security. As African countries work to build robust, adaptable health systems, the AHS Index provides the evidence they need to make targeted investments and demonstrate meaningful capacity improvements over time. However, data-driven financing efforts are only effective alongside political will and the capacity to act.

This World Health Day, standing with science means protecting the systems that make evidence possible and advancing the international cooperation necessary to turn that evidence into action.