Bill Gates thinks there are 8 to 10 promising coronavirus vaccine candidates and one could be ready in as little as 9 months

• Microsoft billionaire and philanthropist Bill Gates wrote in a blog post that he thinks there are currently eight to ten promising candidates for a coronavirus vaccine.
• Gates believes it will take 18 months to develop a vaccine, although he says it could come as soon as nine months or take as long as two years.
• Alongside candidates which use traditional methods, Gates is particularly excited about two new kinds of vaccine: RNA and DNA vaccine.
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There are more than a hundred coronavirus vaccines in the works, and of those eight to ten have caught the eye of Microsoft founder Bill Gates.

Gates is pouring hundreds of millions of dollars into developing a vaccine through his philanthropic organization, the Bill and Melinda Gates Foundation. The foundation has so far has pledged a total of $250 million towards fighting the coronavirus, and Gates recently announced that the organization will dedicate its full resources to the pandemic.

Gates published a blog post on Thursday laying out the process for developing and distributing a vaccine. He wrote that a vaccine is likely to take around 18 months to develop, although he writes in his blog it "could be as little as 9 months or as long as two years."

"As of April 9, there are 115 different COVID-19 vaccine candidates in the development pipeline," Gates writes. "I think that eight to ten of those look particularly promising. (Our foundation is going to keep an eye on all the others to see if we missed any that have some positive characteristics, though.)"

Gates says these promising candidates "take a variety of approaches to protecting the body against COVID-19," going on to explain that there are two main kinds of vaccine — inactivated and live.

Inactivated vaccines contain a dead version of the desired pathogen, whereas live ones contain a smaller but living dose of it. Gates describes these methods as traditional and reliable, but adds they are resource-intensive and slow to develop.

"I'm particularly excited by two new approaches that some of the candidates are taking: RNA and DNA vaccines," Gates writes.

"Rather than injecting a pathogen's antigen into your body, you instead give the body the genetic code needed to produce that antigen itself. When the antigens appear on the outside of your cells, your immune system attacks them—and learns how to defeat future intruders in the process. You essentially turn your body into its own vaccine manufacturing unit."

Although the Gates Foundation has been researching RNA vaccines for almost a decade, they are yet to make it out into the wild. "Since COVID would be the first RNA vaccine out of the gate, we have to prove both that the platform itself works and that it creates immunity. It's a bit like building your computer system and your first piece of software at the same time," says Gates.

A key challenge around producing a vaccine for COVID-19 is that a coronavirus vaccine has never been developed to date.

But the Microsoft billionaire has said numerous times that a return to total normality is impossible without a vaccine.

"Humankind has never had a more urgent task than creating broad immunity for coronavirus. Realistically, if we're going to return to normal, we need to develop a safe, effective vaccine," he writes.