Bill Gates: 'Donald Trump confused on difference between HIV and HPV'

Bill Gates says Donald Trump doesn't know the difference between HIV and HPV. Photo / AP

Donald Trump once struggled to understand the difference between HIV and HPV, billionaire businessman Bill Gates has revealed.

The Microsoft founder told MSNBC that he was quizzed on the difference between the two at a get-together at Trump Tower in December 2016, reports news.com.au.

"He wanted to know the difference between HIV and HPV," Gates said. "So I was able to explain that those were rarely confused with each other."

HPV, or human papilloma virus, affects your skin and the moist membranes lining your body, while HIV, or human immunodeficiency virus, damages the cells in your immune system and weakens your ability to fight everyday infections and disease.

Mr Gates said when he saw Mr Trump again in March 2017 "he asked me if vaccines weren't a bad thing".

"He was considering a commission to look into the ill effects of vaccines, and Robert Kennedy Jr was advising him that vaccines were causing bad things, and I said 'no, that's a dead end, don't do that'. Both times, he wanted to know if there was a difference between HIV and HPV."

Mr Gates said that while he didn't know the difference between HIV and HPV, Mr Trump did know a "scary amount" about his then teenage daughter, Jennifer.

U.S. President Donald Trump speaks during an announcement in the Diplomatic Room of the White House. Photo / AP

"He knew my (show jumping) daughter Jennifer, because Trump has this horseshow thing down in Florida and he went up and talked to Jen, and was being super-nice, and then, 20 minutes later, he flew in, in a helicopter, to the same place," Mr Gates said.

"So clearly he had been driven away and he wanted to make a grand entrance in a helicopter. Anyway, so when I first talked to him, it was actually kind of scary how much he knew about my daughter.

"Melinda (Gates' wife) didn't like that too well," he said.

Mr Gates also revealed that Mr Trump referred to himself in the third person.

"When I walked in, his first sentence kind of threw me off. He said: 'Trump hears that you don't like what Trump is doing.' And I thought, 'Wow, but you're Trump,"' he said.