Biological Weapons: How Disease Becomes a Weapon

What are biological weapons?

Biological weapons are pathogens or toxins that are deliberately released to cause illness, death or disruption. The intent distinguishes them from naturally occurring outbreaks. International law classifies the development, production, stockpiling and use of such agents as illegal, regardless of the disease involved.

Definition and legal status

According to the Biological Weapons Convention, any program that aims to weaponize microbes, toxins, or genetic material falls under the prohibition. The treaty, signed in 1972, obliges signatories to destroy existing stockpiles and refrain from new development.

Historical use of disease as a weapon

Ancient examples

Records from antiquity describe armies contaminating water sources with infected corpses. The siege of Caffa in 1346, for instance, reportedly involved catapulting plague‑infected bodies over city walls, an early form of biological warfare.

20th century programs

During the Cold War, several superpowers pursued large scale programs. The Soviet Union’s “Biopreparat” complex produced anthrax, plague and smallpox variants. The United States conducted defensive research under the name “Project MKNAOMI”, while Japan’s Unit 731 experimented with plague in occupied China.

Modern technological advances

Gene editing and synthetic biology

New tools such as CRISPR allow precise editing of DNA, making it possible to increase a pathogen’s transmissibility or resistance to treatment. Researchers can also synthesize viral genomes from digital sequences, lowering the barrier for a determined actor.

Dual use research

Many studies aimed at improving vaccines or diagnostics also generate knowledge that could be misused. The term “dual use” captures this tension. For example, work on increasing the aerosol stability of influenza viruses can help design better inhalable vaccines, yet the same data could guide a malicious design.

International legal framework

Biological Weapons Convention

The Convention remains the cornerstone of global biosecurity. It requires annual confidence building measures, where states report relevant activities to the United Nations. However, verification mechanisms are limited, relying largely on trust and peer review.

Enforcement challenges

Unlike nuclear weapons, there is no dedicated inspection regime for biological agents. The covert nature of labs, combined with the ease of acquiring genetic material, makes detection difficult. National legislation varies, and some countries lack the capacity to enforce the treaty fully.

Risks to global security

Potential impact of a deliberate outbreak

A single release of a highly contagious pathogen could overwhelm health systems, cause economic loss and trigger panic. Modelling by the Centers for Disease Control and Prevention suggests that a smallpox event could result in millions of cases worldwide within weeks.

Challenges of attribution

Determining the source of an outbreak is scientifically complex. Genetic signatures can point to a laboratory origin, but sophisticated actors may mask traces. Without clear attribution, diplomatic responses risk escalation or misdirected blame.

Efforts to prevent misuse

Surveillance and detection

International networks monitor unusual disease patterns. The World Health Organization coordinates rapid reporting and supports laboratory capacity in low resource settings. Early detection reduces the window for a weapon to spread.

Responsible science initiatives

Many institutions adopt codes of conduct that require risk assessments before publishing sensitive results. The Johns Hopkins Center for Health Security provides guidance on publishing dual use research responsibly.

Key questions for policymakers

• How can verification mechanisms for the Biological Weapons Convention be strengthened without compromising scientific openness?
• What resources are needed to improve global disease surveillance in regions with limited laboratory infrastructure?
• Should there be an international registry for high risk pathogen research, similar to nuclear material tracking?
• How can public health and security agencies cooperate while preserving civil liberties?
• What role should private biotech firms play in reporting suspicious activities?

Addressing these questions requires coordinated action across governments, scientific communities and international organisations. The threat of disease weaponization is not a distant scenario; it is a present challenge that demands vigilance, robust legal tools and a commitment to responsible innovation.