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Merck & Co., Inc., and River Blindness Prevention: The Mectizan Donation Program

In 1987, Merck & Co. announced that it had successfully tested a drug that prevented river blindness and that the company would make the drug available, free of charge, to anyone in the world who needed it. This was important news for the more than 120 million people throughout Africa, Asia and Latin America at risk for this disease. This medical breakthrough and generous donation also posed to be a potential logistical nightmare. How Merck made Mectizan available to millions of people and helped in treatment of river blindness is one of the successful models of public-private partnerships. It also is the largest ongoing donation programs of its kind.

The Problem: River Blindness

River blindness (onchoceriasis) affects an estimated 18 million people in the developing world. It is spread through the bite of the black fly that lives and breeds near streams and rivers. When an infected black fly bites a human it deposits a parasitic worm larvae that produces millions of microscopic worms. As the worms multiply and spread through the host's body it causes severe itching and skin disfigurement, and can cause serious eyesight loss or total blindness.

The Solution

In 1975, a research doctor working in Merck's animal sciences division discovered that there was a close parallel between certain animal parasites and the micro worms that caused river blindness in humans. He found that the medicine used to treat the animal parasites, when applied to the micro worms, eliminated them from the host. With corporate backing, the Merck researcher adjusted the dosage and the formula for human consumption and conducted clinical trials to measure its efficacy and safety. The trials showed that a single oral dose of Mectizan taken annually eliminated the worms for up to a full year. It also showed that the drug must be taken every year for at least 12 years, the life cycle of the microfilaria worms, in order to be eradicated from the host. Clinical trials conducted in seven countries were successful, and in 1987, French regulatory authorities approved Mectizan for human use.

Merck recognized that there was no commercial market for this product. The cost of the product plus its marketing and distribution made it prohibitively expensive for those it was suppose to help. Merck's CEO made the announcement that the company would donate Mectizan to all those who needed it and for as long as it was needed.

Merck had the "cure" but now how to figure out how to get it to the patients. The company decided to distribute and administer the product through local non-government organizations (NGOs) located in the countries where river blindness was prevalent. Local NGOs were asked to demonstrate in proposals their ability for service delivery, record keeping and administrative capabilities, and a commitment for three years. Merck then formed the Mectizan Expert Committee (MEC) and Secretariat, an independent group of public health and tropical medicine professionals under the leadership of Dr. William Foege and the Task Force for Child Survival and Development, to review the NGOs' applications and select its new delivery partners.

Program Partners

  • Mectizan Expert Committee (MEC)
  • World Bank
  • World Health Organization (WHO)
  • More than 30 nongovernmental organizations (NGOs)
  • Dozens of local community health agencies


  • The Mectizan Expert Committee has approved more than 80 service delivery programs in Africa, Latin America, and Yemen.
  • The Merck Mectizan Donation Program has delivered 200 million treatments over a 14-year period.
  • More than 600,000 cases of blindness have been prevented.
  • Infection has been prevented in over 16 million children in 11 West African countries alone.
  • An estimated 25 million hectares of arable land (approximately the size of the United Kingdom) have been reopened for settlement and cultivation as a result of the global efforts to eliminate river blindness.
  • The treatment system that Merck and the Mectizan Donation Program started resulted in the establishment of several other important complementary programs. Among them was the World Bank's African Programme for Onchocerciasis Control in 1995, which raised $131 million over 12 years to help NGOs and local health agencies control the disease through aerial spraying in an additional 19 African countries.
  • The Onchocerciasis Elimination Programme of the Americas, similar to the World Bank's African program is designed to eliminate river blindness as a public health problem in Latin America.

The Mectizan Expert Committee (MEC) and its Secretariat works closely with Merck's Corporate Office of Contributions to monitor the global Mectizan treatment programs, encourage the development of new programs and serve as a liaison with NGOs and government ministries of health. Merck's Office of Contributions oversees the production, packaging, and distribution of all shipments of Mectizan and works closely with workers in the field and the MEC.

In November 1997, 10 years after the program's initiation, Merck & Co. acknowledged that the fight against river blindness was not over. In doing so, Merck's chairman and CEO signed a declaration of intent reiterating the company's commitment to produce and donate Mectizan to treat the disease for as long as needed.

A year later, in October 1998, Merck & Co. announced a major expansion of the Mectizan Donation Program in Africa to begin treating the devastating disease lymphatic filariasis, also known as elephantiasis, in African countries where the two diseases co-exist. In recent years Mectizan has demonstrated its effectiveness against the parasitic filarial worm that causes this disease. The expanded program, which is a collaborative effort with the World Health Organization and GlaxcoSmithKline, seeks to treat the more than 40 million Africans infected by lymphatic filariasis, and bring future relief to the 300 million at risk for the disease.

For more information about the Merck Mectizan Donation Program, contact:
Jeff Jacobs, Manager
Merck Mectizan Donation Program
Merck & Co., Inc.
Office of Contributions

Case studies
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The Mectizan Donation Program

The Global Alliance to Eliminate Lymphatic Filariasis

The Central American Hand Washing Initiative

Healthy Children, Healthy Futures Program

The Partnership for Maternal and Child Health


African man receiving river blindness treatment




Onchocerciasis prevention poster