12. Biological weapons and health security threats

Biological weapons comprise bacteria, viruses or toxins disseminated through a delivery mechanism to inflict harm and are prohibited under international law. The principal legal instrument banning biological warfare is the 1972 Biological and Toxin Weapons Convention (BWC). The BWC is moving towards universality, with Comoros and Kiribati acceding to the convention in 2025, taking the number of states parties to 190.

The wider biological warfare regime includes the 1925 Geneva Protocol, which prohibits the use of chemical and biological weapons in war, and a growing array of other measures, including export control regimes like the Australia Group, the United Nations secretary-general’s mechanism for investigation of alleged use of chemical and biological weapons, and UN Security Council Resolution 1540. These broader measures all serve to bolster aspects of the prohibition and prevention of biological weapons.

Biological weapon disarmament and non-proliferation

There were two significant anniversaries in the history of biological weapon prohibition in 2025: the centenary of the 1925 Geneva Protocol and the 50th anniversary of the entry into force of the BWC. The anniversaries reaffirmed the strength of the norm against biological weapons while underscoring the difficulty of translating that norm into effective institutional capacity.

The 2025 sessions of the working group on strengthening the BWC were defined by a shift from conceptual debate to drafting concrete text, although procedural deadlocks at the end of the year prevented formal adoption of a final substantive report. Similarly, the 2025 Meeting of States Parties of the BWC was largely defined by procedural deadlock and the inability to reach consensus on substantive outcomes. At the First Committee of the UN General Assembly, the United States encouraged countries to join a USA-led artificial intelligence (AI) verification initiative to enhance the enforcement and monitoring of the BWC.

Technological advancements and risks

Advances in AI, synthetic biology and laboratory automation are expanding the scale, speed and accessibility of the life sciences, intensifying both their beneficial and destabilizing potentials. These developments place new demands on governance systems that were largely designed for a different technological era. The challenge for arms control and biosecurity frameworks revolves around institutional adaptation, implementation and trustbuilding across increasingly complex scientific ecosystems.