22. Calls upon all States to take all appropriate measures to develop sustainable health systems and social services and to ensure access to such systems and services without discrimination and to pay particular attention to adequate food and nutrition to prevent disease and malnutrition, to prenatal and post-natal health care, to the special needs of adolescents, to reproductive and sexual health and to threats from substance abuse and violence, in particular to all vulnerable groups, and calls upon all States parties to take all necessary measures to ensure the right of all children, without discrimination, to the enjoyment of the highest attainable standard of health;