Trump calls the virus "a brilliant enemy." He adds, "Antibiotics used to solve every problem" but now "the germ has gotten so brilliant that the antibiotic can't keep up with it." He adds, "There's a whole genius to it." He adds of the virus, "It's hidden, but it's very smart."

I'd be cautious in asserting that Trump was suggesting that antibiotics used to be effective against viruses. I took it as more, like, "oh here's another thing I think about something." He's just talking.