Diplomats meeting in San Francisco, California to form the United Nations agree that throughout modern history, there has been insufficient collaboration between countries to control the spread of dangerous diseases across the world. Together they decide on the need for a global organization overseeing global health and plan for the creation of WHO.

WHO's constitution is drafted and then approved at the International Health Conference in New York City.

WHO establishes the first ever global disease-tracking service, with information transmitted via telex.

WHO's Constitution comes into force on 7 April -- a date we now celebrate every year as World Health Day. Following the mandate established for it by Member States, WHO begins its first two decades with a strong focus on mass campaigns against tuberculosis, malaria, yaws, syphilis, smallpox and leprosy, among other communicable diseases transmitted from person to person or animals to people.

The great era of discovery of present-day antibiotics begins, and WHO begins advising countries on their responsible use.

Jonas Salk and Albert Sabin discover, respectively, the inactivated wild poliovirus vaccine (given by injection) and the attenuated live-virus vaccine (given orally), paving the way for mass global campaigns facilitated by WHO that have led to the near-eradication of polio.

The vaccine against measles becomes available, and the licensing of vaccines against mumps and rubella occurs during the six years that follow.

The World Health Assembly establishes the first International Health Regulations, which represent an agreement between WHO Member States to work together to prevent and respond to acute public health risks that have the potential to cross borders and threaten people worldwide.

The Special Programme of Research, Development and Research Training in Human Reproduction (HRP) is created at WHO. It is the sole body within the UN system with a global mandate to carry out research into sexual and reproductive health and rights.

WHO founds the Expanded Programme on Immunization to bring life-saving vaccines to all the World's children.

WHO founds and begins hosting the Special Programme for Research and Training in Tropical Diseases (TDR), a global programme of scientific collaboration that helps facilitate, support and influence efforts to combat diseases of poverty. By 2016, five of the eight diseases the I programme was created to tackle are close to elimination.

The first Essential Medicines List is published. This core list outlines the medicines that a basic health system needs. Each medicine is selected based on evidence for its safety, effectiveness and value for money.

The International Conference on Primary Health Care, in Alma-Ata, Kazakhstan, sets the aspirational goal, "Health for All", laying the groundwork for WHOs current call for Universal Health Coverage.

Following an ambitious 12 year global vaccination campaign led by WHO, smallpox is eradicated.

Human immunodeficiency virus, which causes AIDS, is discovered.

The World Health Assembly calls for the global eradication of polio, at a time when the disease paralysed more than 350,000 children every year in more than 125 endemic countries. The Global Polio Eradication Initiative (GPEI), is launched. Since then, the incidence of polio has been reduced by more than 99% and only two countries remain endemic to wild poliovirus. See document: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://apps.who.int/iris/bitstream/handle/10665/164531/WHA41_R28_eng.pdf?sequence=1&isAllowed=y

The DOTS strategy for reducing ( the toll of tuberculosis (TB) is launched. At end 2013, more than 37 million lives had been saved through TB diagnosis and treatment under this strategy.

Major players in global immunization, including WHO and other key UN agencies, leaders of the vaccine industry, government representatives and major foundations agree to work together through a new partnership: the Global Alliance for Vaccines and Immunization (GAVI). Its role will be to overcome barriers preventing millions of children from receiving vaccines.

At the Millennium Summit in September 2000, the largest gathering of world leaders in history adopts the UN Millennium Declaration, committing nations to a new global partnership to reduce extreme poverty and setting out a series of time-bound targets, with a deadline of 2015. They become known as the Millennium Development Goals (MDGs) and include specific goals for health. The WHO Global Outbreak Alert and Response Network is established to detect and combat the international spread of outbreaks.

The Twenty-sixth special session of the United Nations General Assembly adopted the Declaration of Commitment on HIV/AIDS as a matter of urgency to address the HIV/AIDS crisis worldwide as well as to secure a global commitment to enhancing coordination and intensification of national, regional and international efforts to combat it in a comprehensive manner.

The Global Fund to fight AIDS, Tuberculosis and Malaria, a new partnership and funding mechanism initially hosted by WHO, is created in collaboration with other UN agencies and major donors.

On World AIDS Day (1 December 2003) WHO launched the 3 by 5 initiative to provide antiretroviral treatment to three million people living with HIV in developing countries and those in transition by the end of 2005.

The World Health Assembly unanimously adopts WHOs first global public health treaty, the WHO Framework Convention on Tobacco Control, which aims to reduce tobacco-related deaths and disease worldwide.

The UN Road Safety Collaboration was established in 2004. WHO and World Bank launched the first ever world report on road traffic injury prevention. Later on, UN General Assembly adopted a resolution inviting WHO to act as coordinator on road safety issues across the UN system.

The Strategic Health Operations Centre is built to serve as the nerve centre of the networks of emergency operations centres and of WHOs global alert and response. It is used for the first time to assist with emergency coordination following the Indian Ocean tsunami disaster.

The International Health Regulations are revised, giving countries clear and tested guidelines for reporting disease outbreaks and other public health emergencies to WHO and triggering response systems to isolate and contain threats.

The number of children who die before their fifth birthday declines below 10 million for the first time in recent history.

World Health Assembly adopts a resolution on the health of migrants, fostering global actions to improve their health and well being. The first and second Global Consultation on Migrant Health, organized by WHO, IOM and the Government of Spain took place in 2010, and by the Government of Sri Lanka in 2017. See: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/http://apps.who.int/iris/bitstream/handle/10665/23533/A61_R17-en.pdf?sequence=1

The World Health Statistics report notes a global shift from infectious diseases to noncommunicable diseases, with heart disease and stroke emerging as the world's number one killers. This new l evidence prompts WHO to strengthen its focus on noncommunicable diseases.

WHO issues a menu of options for raising sufficient resources and removing financial barriers so that all people, especially those who have limited funds to spend on health care, have access to essential health services. The objective is a move towards Universal Health Coverage.

Adoption of the Pandemic influenza preparedness framework paving the way for equitable access to countermeasures during pandemics.

For the first time WHO Member States set global targets to prevent and control heart disease, diabetes, cancer, chronic lung disease and other diseases.

WHO adopts its first global Comprehensive Mental Health Action Plan to monitor and promote essential scale up of services for people living with mental health conditions and psychosocial disabilities.

The biggest outbreak of Ebola virus disease ever experienced in the world strikes West Africa. The WHO Secretariat activates an unprecedented response to the outbreak, deploying thousands of technical experts and support staff and medical equipment; mobilizing foreign medical teams and coordinating creation of mobile laboratories and treatment centres.

HIV treatment coverage was expanded rapidly with well over 17 million people living with HIV on antiretroviral therapy by the end of 2015; new HIV infections and deaths declined; dozens of countries moved towards the elimination of mother-to-child transmission of HIV. // Cuba became the first country in the world to receive validation from WHO that it has eliminated mother-to-child transmission of HIV and syphilis.

In 2015, the WHO European Region was the first Region in the world to achieve the interruption of indigenous malaria transmission. To date, the European region maintains malaria free status.

UN Summit sign off on 2030 Sustainable Development Goals (SDGs), which move beyond the MDGs. The SDGs maintain poverty eradication, health, education, food security and nutrition as priorities but additionally covers a broad range of economic, social and environmental objectives, mainly, no one should be left behind. WHO’s commitment to the SDGs and the principal of leaving no one behind are enshrined in a WHA resolution and the shared UN framework for action on equality and non-discrimination.

The first ever child-friendly formulations of anti-TB medicines, which are water-dispersible tablets, was introduced. They offer the opportunity to simplify and improve treatment for children around the world and are therefore likely to enhance adherence and completion of treatment, as well as to prevent the development of drug resistance.

The goal of one billion people treated for at least one Neglected Tropical Disease in a single year is met for the first time.

WHO announces zero cases of Ebola in West Africa, but warns that flare-ups of the disease are likely to continue and that countries in the region need to remain vigilant and prepared.

Under the International Health Regulations, WHO convenes the Emergency Committee, which concludes that a cluster of neurological birth defects (underdeveloped brains), that appear to be related to infection with Zika virus among pregnant women, represents a Public Health Emergency of International Concern.

Nigeria, long considered the global epicentre of poliovirus, reports its last wild poliovirus, paving the way for certifying the African Region free of such strains. Five of six WHO Regions are today certified free of wild poliovirus and two of three wild poliovirus strains have been globally eradicated.

UN General Assembly adopts a political declaration on antimicrobial resistance (AMR) and calls for the establishment of an Ad-hoc inter-agency coordination group on antimicrobial resistance to provide practical guidance to ensure global action against AMR.