1990: The universe of public health
The combined efforts of many organizations, especially UNICEF and WHO, succeeds in immunizing 80 percent of the world's children against six infectious diseases (polio, diphtheria, pertussis, tetanus, measles and tuberculosis). But newer vaccines are still not being distributed much beyond developed nations. The Children's Vaccine Initiative (CVI) is launched at the World Summit for Children in New York to push the development of new vaccines for the Third World.

Mid-1990s: Financial strains and politics fracture vaccination efforts
Several forces contribute to the decline in global immunizations, including a fracturing of resources as the AIDS epidemic over-shadows vaccination efforts. WHO and UNICEF are engaged in fierce turf battles over who should set policy on vaccines. The Children's Vaccine Initiative stalls and eventually fails for lack of funding. Donors and the pharmaceutical industry lack interest in vaccine development and improved immunizations. Immunization rates decline worldwide as the global health community fractures.

2000: Bill Gates helps establish new public health alliance
At the World Economic Forum in Davos, Switzerland, Bill Gates joins the leaders of WHO, UNICEF, the World Bank and others to announce the start of the Global Alliance for Vaccines and Immunization (GAVI). GAVI is established as a collaborative venture with all the players given equal say and responsibility. Funded largely by Gates so far, this new global immunization effort aims to build sustainable vaccination programs and reduce poverty. It's a new approach to worldwide immunization, moving from the traditional welfare model in global health to more of an incentive-based, investment program. If it succeeds, some say it could be the greatest public health achievement ever.