Bill Gates, the cofounder of Microsoft, said during a recent meeting with staff of his foundation that President Donald Trump asked him on two different occasions what the difference was between HIV and HPV.

In footage obtained by and aired Thursday on MSNBC's All in with Chris Hayes, Gates, speaking to staff at the Bill and Melinda Gates Foundation during a recent meeting, recounts his first encounters with the president.

The Microsoft cofounder and global philanthropist said he met with Trump on two occasions in December 2016 and March 2017 to discuss how the new president could drive advances in science and innovation.

"You know, pick things you want to do that are big, HIV vaccine — you could accelerate that," Gates recalled telling Trump. "Be associated with innovation."

Gates said during those meetings Trump asked him if vaccines weren't bad, because he was considering creating a commission to look into any negative effects of vaccines.