The following was published in the Wall Street Journal on February 28, 2013.

More than three decades ago, each of us started a technology company based on a big idea—and each company found success based on a culture of innovation and accountability. In recent years, we've brought that same approach to our philanthropy and have joined forces on two major global projects: reducing tobacco use, which threatens to kill one billion people by the end of this century; and providing women with access to information and services they need to plan their families, leading to safer births and fewer maternal deaths.

Now, we are teaming up to tackle one of the most ambitious public-health goals ever set: eradicating polio, a disease that has haunted humanity at least since ancient Egypt. One of us (we're not saying which one) was born at a time when the U.S. president was battling the effects of polio, and both of us are old enough to remember the great fears that polio epidemics generated among parents and children in the 1950s. While the Salk and Sabin vaccines ended the threat of polio in America and much of the developed world during the 1960s, polio continues to paralyze children in a handful of developing countries.

As recently as 1988 - the year the world adopted eradication as a goal—polio was circulating in more than 125 countries, and more than 350,000 children were paralyzed annually. Since then, thanks to a massive world-wide effort, the number of cases is down by more than 99%. In 2011, India, considered the most difficult place to achieve eradication, was declared polio-free. Last year, we witnessed the steepest drop in new cases in a decade. In 2012, there were fewer than 225 cases and the spread of the virus has to be stopped in only three countries: Afghanistan, Nigeria and Pakistan. That is the fewest cases in the fewest countries ever.

However, the last 1% is the most difficult of all. In Afghanistan, Nigeria, and Pakistan, vaccinators travel long distances across difficult terrain, and some parents won't allow their children to be vaccinated. Security is also a concern, as health workers in Pakistan and Nigeria have recently been targeted by militant groups.

Just two weeks ago, 10 people, including a pregnant woman and nine health workers, were shot dead at two health clinics during a polio immunization campaign in Nigeria. Only two months before, health workers in Pakistan also were killed. We believe that the best way we can honor their lives is to complete their work.

The Gates Foundation has been investing in polio eradication for many years, and Bloomberg Philanthropies is now joining the effort with a $100 million commitment. Together, we are supporting the Global Polio Eradication Initiative's new six-year strategic plan for eradication.

The plan is based on data collected and lessons learned most recently during India's success against polio. The plan also includes innovative tactics and cutting-edge tools, like geographic information-system maps that combine cartography and database technology to help locate children who have not been reached by vaccinators. The plan also provides greater assurance to donors that efforts to end polio will have a broader impact than just protecting children from this preventable and debilitating disease by eradicating it forever.

The Global Polio Eradication Initiative takes an approach that differs from past strategies, which featured short-term goals instead of a full plan for finishing the job. This led to year-to-year funding support, often resulting in financial shortfalls that hampered progress and left donors frustrated.

With this new plan, there is finally a clear sense of the key milestones needed to end polio, a complete timeline, and an accounting of how much money it will cost in total, which is an estimated $5.5 billion. Of course, the plan will only be successful if it is fully funded by governments, financial institutions such as the World Bank and Islamic Development Bank, and philanthropic organizations like the ones we run.

In September, the presidents of all three endemic nations committed their full support. And now with the commitment by Bloomberg Philanthropies as of Feb. 28, there is even more reason to be optimistic.

Some might wonder why so much effort and money is being devoted to fight a disease that is contracted by fewer people than can fit on a commercial airplane. The answer is that keeping the number of new cases this low cannot be sustained year after year—polio will make a comeback if it is not eradicated.

To capitalize on the current momentum, fast action is needed. Furthermore, eradication will save billions of dollars over the long term. When success is achieved, the world will have a workable, scalable model for global vaccination—a blueprint for success that can be used time and again to reach children throughout the developing world and prevent disease on an unprecedented scale.

Thinking big is an important part not only of successful businesses, but also of successful societies. It reflects a belief in human ingenuity and the ability to overcome even the toughest problems facing the world.

Michael Bloomberg is the mayor of New York and founder of Bloomberg L.P.