Deborah Birx, the White House coronavirus task force coordinator, said she had not seen research to support the theory that heat could kill viruses.

“I mean, certainly, fever is a good thing when you have a fever because it helps your body respond. But I have not seen heat for viruses,” she said during the briefing.

Bill Bryan, the acting undersecretary of Science and Technology at DHS, at the evening briefing described the research on how sunlight, heat, and humidity affects the virus on various surfaces and said they were the coronavirus's weak spots. But he said the study hadn't looked at sunlight as a treatment, that the work hadn't been peer-reviewed and that the findings shouldn't take away from other guidance released by the White House and CDC, including social distancing and mitigation.

“It would be irresponsible for us to say that we feel the summer will totally kill the virus,” Bryan said. “This is just another tool in our tool belt. Another weapon in the fight that we can add to it and in the summer, we know that summer-like conditions are going to create an environment where the transmission can be decreased and that's an opportunity for us to get ahead.”