https://www.cnet.com/news/bill-gates-explains-to-trump-that-hiv-and-hpv-are-different-diseases-twice/

Among other anecdotes, Gates is seen telling an audience about how, in both of his meetings with Trump, the president asked if there's a difference between HIV and HPV. The crowd was of Bill & Melinda Gates Foundation employees, according to MSNBC. 

"He wanted to know if there was a difference between HPV and HIV," Gates is seen saying, "so I was able to explain that those are rarely confused with each other."