In May 2025, the 78th World Health Assembly (WHA) adopted resolution WHA78.28, Effects of Nuclear War on Public Health, reaffirming the critical role of the World Health Organization (WHO) in assessing, documenting and communicating the health consequences of nuclear weapons and nuclear war. The resolution recognizes that the catastrophic effects of nuclear weapons pose an existential threat to human health, health systems, food security, the environment and sustainable development. The resolution requests the Director-General to update WHO's body of evidence on the consequences of nuclear war and to report findings to the WHA in 2029. It also encourages WHO engagement with relevant stakeholders and other United Nations bodies and international organizations, in accordance with their respective mandates, to strengthen scientific understanding of the effects of nuclear war.

WHO has a long history of engagement on peace, health and nuclear weapons. In the 1980s and early 1990s, WHO produced landmark reports on the effects of nuclear war on health and health services, concluding that no effective public health response would be possible following a large-scale nuclear conflict. These reports became foundational references for understanding the humanitarian consequences of nuclear weapons:

• WHO (1983). Effects of Nuclear War on Health and Health Services
• WHO (1987). Effects of Nuclear War on Health and Health Services: Second Report
• WHO (1993). Health and Environmental Effects of Nuclear Weapons

Since those reports were published, scientific knowledge has advanced considerably. In addition to further development of nuclear weapons technology, new evidence has emerged on:

• The immediate health impacts of nuclear detonations, including burn injuries, trauma, radiation exposure and mass casualties.
• The collapse of health systems and essential services following a nuclear attack, including cascading effects on infrastructure and supply chains.
• Long-term environmental contamination and ecological disruption.
• Global climatic effects, including "nuclear winter" scenarios and associated food insecurity and famine risks.
• The disproportionate impacts on vulnerable populations and future generations.

At the same time, growing international concern regarding nuclear risks amid escalating geopolitical tensions prompted renewed calls for WHO to provide updated authoritative, evidence-based assessments of these threats as a matter of global public health. The resolution WHA78.28 also notes concerns expressed by Member States in the UN’s Pact for the Future regarding the growing risk of nuclear war and recommitments to nuclear disarmament.

How did the resolution come about?

The adoption of WHA78.28 followed several years of advocacy by Member States, public health experts, scientific and professional organizations and civil society groups working at the intersection of health, peace and disarmament.

The resolution built upon earlier WHA discussions on the relationship between health and peace, including WHA77.9 (2024), and was informed by growing international attention to the humanitarian and public health consequences of nuclear weapons. It also aligns with broader United Nations initiatives, including UN General Assembly resolution 79/238 on nuclear war effects and scientific research, which mandated the UN Secretary-General to establish an independent Scientific Panel on the Effects of Nuclear War, tasked with reporting to the UN General Assembly in 2027 on the physical and societal consequences of a nuclear war on a local, regional and planetary scale.

Medical and public health organizations played an important role in highlighting the need for updated scientific evidence. Groups such as International Physicians for the Prevention of Nuclear War (IPPNW) and International (ICAN), recipient of the 1985 Nobel Peace Prize, have consistently called for renewed WHO engagement on this issue and encouraged Member States to support the resolution.

The draft resolution was proposed by:

Burkina Faso | Ecuador | Fiji | Guatemala | Iraq | Kazakhstan | Marshall Islands | Micronesia (Federated States of) | New Zealand | Peru | Samoa | Vanuatu

The resolution’s lead sponsors were the Marshall Islands, Samoa, and Vanuatu, reflecting strong support from Pacific Island States, which have direct historical experience with the health and environmental consequences of nuclear weapons testing and have been longstanding advocates for greater international attention to nuclear harms.

Adoption by the World Health Assembly

On 27 May 2025, the World Health Assembly adopted WHA78.28 following a recorded vote. The resolution received broad support from Member States, reflecting growing recognition that the prevention of nuclear war is a fundamental public health issue and that WHO has a unique mandate to provide authoritative, international and independent scientific and health expertise in this area. At its adoption, the initiative gained even broader cross-regional support, with 34 co-sponsors: Austria, Brazil, Burkina Faso, Colombia, Costa Rica, Dominican Republic, Ecuador, Fiji, Guatemala, Indonesia, Iraq, Ireland, Kazakhstan, Kenya, Kiribati, Kyrgyzstan, Maldives, Malta, Marshall Islands, Mexico, Micronesia, Namibia, Nauru, New Zealand, Panama, Peru, Philippines, Samoa, San Marino, South Africa, Thailand, Tuvalu, Uzbekistan, and Vanuatu.

Implementation of WHA78.28

WHO is implementing the resolution through a programme of work focused on:

• Strengthening the evidence base: WHO is reviewing the current scientific literature on the health, humanitarian and environmental consequences of nuclear weapons and nuclear war, while identifying critical knowledge gaps that require further research.
• Supporting scientific assessment: WHO contributes its public health expertise to international scientific efforts examining the effects of nuclear war and their implications for health systems, emergency preparedness, food security and population health.
• Monitoring emerging evidence: Implementation includes assessing recent scientific findings related to radiation exposure, climate impacts, displacement, infrastructure and supply chain vulnerabilities, socio-economic, health system and mental health consequences and long-term effects on human populations and ecosystems.
• Reporting to Member States: In accordance with WHA78.28, WHO Secretariat will report to Member States through its governing body – WHA in 2029.

In order to achieve this goal, a WHO Expert Working Group (EWG) is being established, including experts in the following areas:

• Expertise on nuclear weapons, their deployments, policies and decision-making processes contributing to likely scenarios for nuclear war
• Radiation health effects (short & long term)
• Clinical management of trauma, burns and radiation injuries, and mental health impact of a nuclear detonation
• Broad systems approaches in public health, health service organisation, availability of pharmaceuticals/vaccines/equipment, and overall delivery of health services
• Health-relevant engineering/infrastructure, including in relation to shelter/housing, energy, food, water, waste disposal, sanitation, supply chains, communications, transport, mobility
• Disaster response in military conflict involving nuclear weapons
• Health impact of nuclear weapons testing
• Mental health consequences related to the use of nuclear weapons
• Communication and information systems, mis-and disinformation and cyber- and AI risks
• Social sciences: human displacement, health economics, trade and dependencies in essential goods and services
• Agriculture, food and water supply and safety
• The health impacts of climate change
• Other/unclassified

WHA resolutions that are the basis for this study:

Thirty-fourth World Health Assembly, Geneva, 4-22 May 1981 | Thirty-sixth World Health Assembly, Geneva, 2-16 May 1983  | Fortieth World Health Assembly, Geneva, 4-15 May 1987 | Forty-sixth World Health Assembly, Geneva, 3-14 May 1993 | WHA78.28: Effects of Nuclear War on Public Health

WHA78.28: Effects of Nuclear War on Public Health

Historic WHO reports:  WHO (1983). Effects of Nuclear War on Health and Health Services | WHO (1987). Effects of Nuclear War on Health and Health Services: Second Report | WHO(1993). Health and Environmental Effects of Nuclear Weapons

Partner and civil society resources:

Treaty on the Prohibition of Nuclear Weapons | UNODA Independent Scientific Panel on Effects of Nuclear War | IPPNW Peace and Health Blog: Re-engaging WHO in Nuclear Weapons and Health

Scientific and technical reports:

Kamran Abbasi, et al. Ending nuclear weapons, before they end us | Advice for the Public on Protection in Case of a Nuclear Detonation | Discussion Guide: Saving Lives After a Nuclear Detonation | Planning Guidance for Response to a Nuclear Detonation | Health System Preparedness for Nuclear and Radiological Disasters: A Review | Public health and nuclear winter: addressing a catastrophic threat

The 78th WHA Side Event organized by the International Physicians for Preventing Nuclear War (IPPNW) - an NGO in Official Relation with WHO

Over 130 health journals call for renewed WHO mandate on health effects of nuclear war, May 2025

78th World Health Assembly, May 2025: The WHA resolution (WHA78.28), "Effects of nuclear war on public health," calling for an updated WHO study on the effects of nuclear war on health and health services, was passed by a vote of 86-14, with 28 abstentions.

The statement of A. Sokimi at the 18th coordination meeting of the WHO REMPAN, June 2026