Cain had posted a photo of himself and others at the June Trump rally in Tulsa. None of the people in the photo appeared to be wearing face coverings. After his diagnosis, the Trump campaign said the president had not personally met with Cain at the rally.
He had made similar remarks last week - but officials were quick to correct him, and suggested it was a joke.
Health officials also said cloths masks should be washed normally, and surgical masks replaced after use.
Referring to his earlier comments, Mr Duterte said: "They [critics] said, āDuterteās insane.ā Stupid! If Iām insane, you should be the president, not me.
"What Iāve said was true. If alcohol isnāt available, especially for the poor, just go to a gasoline station, and use [gas] to disinfect.
āI am not joking. I am not joking. Youā¦ you try to get inside my brain.ā
Iām still not getting why people think that children arenāt capable of spreading COVID-19, when adults blame them for spreading other respiratory viruses faster than the speed of light! And this oneās even more highly contagious, with the asymptomatic part being really scary.
I personally will not feel safe until we have a vaccine for it. Iām not in morbid fear, but this is fucking scarier than anything Iāve ever encountered, and Iāve been close to death a couple of times. Okay, like casual acquaintance (food poisoining and nearly-bursting appendix, NOT at the same time, fortunately) with death.