This year's theme is international health security. The aim of the Day is to urge governments, organisations and businesses to "Invest in health, build a safer future". Emerging and epidemic-prone diseases and outbreaks, such as SARS and avian flu, as well as the continuing spread of HIV/AIDS, humanitarian emergencies, and other acute health threats can all be defined as public health emergencies.

International health security is the first line of defence against health shocks that can devastate people, societies and economies worldwide. Implementation of the International Health Regulations (IHR) from June 2007 will help to build and strengthen mechanisms for outbreak alert and response at national and international levels, and contribute to making the world more secure.

To mark World Health Day 2007, a high-level global debate on 2 April 2007 in Singapore will raise the profile of international health security. The debate, involving the WHO Director-General together with political and opinion leaders, will be a dynamic forum to discuss health security challenges and find solutions for how partners can work together to prepare for and respond to acute threats to health.