The International Health Regulations are a code of practices and procedures to prevent the spread of disease. They are a legally binding international instrument that prescribes measures to States for preventing the transboundary spread of infectious diseases. The code of procedures and practices include routine measures at airports and seaports, to ensure maximum security against the international spread of diseases with minimum interference in international world traffic. The IHR set out roles and responsibilities for WHO and individual countries, for responding to a limited range of disease outbreaks.