Here's what Bill Gates considers his 'greatest achievement'—and what he hopes to accomplish next

Bill Gates
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Creating a software company with a $600 billion market value is a huge achievement. Meanwhile, Microsoft co-founder Bill Gates considers his work helping to eradicate polio one of his biggest accomplishments as well.

In a Reddit thread earlier this year, the billionaire was asked, "What do you personally find as your greatest achievement?"

He responded, "I still think the chance to be part of the software revolution empowering people was the biggest thing I have gotten to do."

He adds that the work the Bill and Melinda Gates Foundation is doing is "super promising." "Right now I am very focused on making sure we successfully eradicate polio," he wrote. "That will be amazing if we do it. As good as shipping even the best software product."

Gates has made the eradication of polio one of his top philanthropic priorities. His foundation has contributed nearly $3 billion toward eliminating the disease by 2020.

The billionaire thinks the last outbreak could occur by the end of this year.

"Progress in fighting polio might be one of the world's best-kept secrets in global health," he acknowledges in the foundation's 2017 annual letter. "If things stay stable in the conflicted areas, humanity could see its last case of polio this year."

Polio is a "crippling and potentially deadly infectious disease," according to the Center for Disease Control. The virus invades the nervous system and can cause paralysis in just hours. Among those paralyzed, 2 percent to 10 percent die because their breathing muscles have become immobilized.

Since 2007, the Gates Foundation has contributed technical and financial resources to accelerate vaccination campaigns, provide routine immunization and polio surveillance partnerships as well as help fund more effective vaccines.

And the numbers show the extent of their charitable deeds. In 1998, the poliovirus was present in over 125 countries and paralyzed 350,000 people every year, mostly children.

Since then, polio cases have been reduced by 99 percent, saving 13 million young children from paralysis. Today, there are only twelve known cases of the wild poliovirus, according to Jay Wenger, who leads the Gates Foundation polio eradication efforts.

"In the last couple of years, we've seen unprecedented progress," Wenger tells CNBC. "We are closer than ever, and we're optimistic that we can see the end of wild poliovirus disease by as early as this year."

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See also:

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The plan for Bill and Melinda Gates' $1.7 billion investment in America's public education system