Thomas Goetz

The company agreed to give away the drug for free, as much as needed and as long as needed, as the company's chairman said at the time.

Within a few years, ivermectin was being distributed to whole villages, whole countries.

Soon, people started returning to the rivers in a land rush, as villages and communities were reborn with hope.

And then another triumph.

In the mid-1990s, ivermectin was proven effective for treating lymphatic filariasis, another widespread parasitic disease.

In this case, worms delivered by a mosquito bite.

This disease afflicts 100 million people and causes chronic swelling in the limbs and genitals, leading to horrible conditions like elephantiasis.

Again, Merck donated the drug for free.

Forty years after these triumphs, we now know that ivermectin works against a great many parasites, and it is easy to take just one or two pills a year.

It gives countries a fighting chance to push back on disease and to reclaim land that has been abandoned due to infestation.

To date, five countries have eliminated river blindness outright, and several more are really close.

And all along, Merck has sold a drug under the brand name HeartGuard to prevent heartworms and hookworms in dogs.

These products quickly became the top-selling veterinary medicines in the world, earning more than $1 billion annually.

So yeah, Merck made their money, as they deserved to.

And in 2015, Satoshi Omura and Merck's William Campbell were awarded the Nobel Prize in Medicine for their discovery of ivermectin.

Here is Campbell accepting the honor.

We could end our story here.

A miracle drug, a Nobel Prize, millions of lives improved, billions of dollars earned.

Somehow everyone is a winner.

What a story.