Retired MSD Scientist
William Campbell Wins
Nobel Prize

William C. Campbell, Ph.D., shares 2015's Prize for discoveries related to avermectin, which in turn led to a treatment for river blindness. Here's how Dr. Campbell, fellow MSD researcher Dr. Mohammed Aziz and other MSD colleagues helped change the world for the better.

When MSD scientist William Campbell and Japanese microbiologist, Satoshi Omura, collaborated on a microbe screening program more than 30 years ago, they could not have predicted that their discoveries would one day help protect the eyesight of millions in Latin America, Africa and Yemen – nor that their efforts would garner them the world’s highest recognition of scientific achievement. But on October 5, 2015, the Nobel Assembly announced that Drs. Campbell and Omura were jointly awarded the 2015 Nobel Prize in Physiology or Medicine for their discovery of avermectin, an antiparasitic agent from which ivermectin is derived. Ivermectin is known as MECTIZAN outside the United States. A third recipient, Youyou Tu of China, was recognized for her work leading to the discovery of the antimalarial agent artemisinin.

“Diseases caused by parasites have plagued humankind for millennia and constitute a major global health problem,” the Assembly wrote in its announcement. “This year’s Nobel Laureates have developed therapies that have revolutionized the treatment of some of the most devastating parasitic diseases.”

Learn more about the 2015 Nobel Prize in Physiology or Medicine

Through our Mectizan Donation Program, we have been working with partners for nearly three decades to make this medicine available, free of charge, to all those affected by river blindness. We remain committed to bringing the best that our science and innovation have to offer to solve the world’s global health challenges.
— Ken Frazier, chairman and CEO, MSD

Ken Frazier,
chairman and CEO


In the 1970’s Dr. Campbell was a parasitologist at MSD Research Laboratories in Rahway, N.J., where he led what he once recalled was a “complicated and unglamorous search” to find a new treatment for parasites in animals. His team finally found what it was looking for in soil sample No. OS3153 from Dr. Omura’s team in Japan. The discovery of avermectin was a major milestone in the treatment of parasitic disease.

Further research in the mid-to-late 1970s by Dr. Campbell and his colleagues at MSD led to the development of ivermectin and the discovery that it was effective against river blindness in humans.

Onchocerciasis, more commonly known as “river blindness,” is a debilitating disease endemic to parts of Africa, Latin America and Yemen. It is transmitted through the bite of black flies and can cause intense itching, disfiguring dermatitis, eye lesions and, eventually, blindness.

Following the breakthrough lab work by Dr. Campbell, another MSD researcher, the late Dr. Mohammed Aziz, championed the clinical development of ivermectin. Clinical trials in Africa sponsored by MSD and the World Health Organization (WHO) and spearheaded by Dr. Aziz confirmed the effectiveness of ivermectin as a treatment for river blindness.


In 1987, MSD’s then CEO Dr. P. Roy Vagelos announced, in an unprecedented act of global healthcare leadership, that MSD would donate ivermectin – as much as needed for as long as needed – with the goal to help eliminate river blindness. MSD recognized in order to reach this goal, many organizations with unique skills would need to work together as a team. As a result, MSD created the Mectizan Donation Program (MDP). Operating from the Atlanta-based Task Force for Global Health, the MDP coordinates activities between MSD, WHO, the World Bank and a range of public and private stakeholders.

In 1998, MSD expanded its commitment from the Mectizan Donation Program to include donating ivermectin for another disease, lymphatic filariasis (LF), also known as elephantiasis, in African countries and Yemen where it co-exists with river blindness. For LF, ivermectin is administered with albendazole, a drug donated by GSK.

Today, the Mectizan Donation Program is the longest-running disease-specific drug donation program and public-private partnership of its kind. It reaches more than 250 million people in the affected areas annually, with more than 2 billion treatments donated since 1987.


people annually


doses to date

Both river blindness and lymphatic filariasis on are the WHO's list of neglected tropical diseases targeted for elimination globally. Several countries in Africa are making significant progress towards eliminating both diseases. In Latin America,three countries - Colombia, Ecuador and Mexico - have already received WHO verification of river blindness elimination.

The importance of ivermectin for improving the health and wellbeing of millions of individuals with river blindness and lymphatic filariasis, primarily in the poorest regions of the world, is immeasurable. Treatment is so successful that these diseases are on the verge of eradication, which would be a major feat in the medical history of humankind, the Nobel Assembly stated.