He said the research suggested that people should spend time in the sun and that air conditioning temperatures may need to be increased.
He stressed that this did not mean that people should abandon physical distancing or stop practising personal hygiene as temperatures rise.
“This is just a tool in our tool box,” Bryan said.
Reporters at the briefing immediately questioned the implications of the research given New Orleans, which has a warm and humid climate year round, has experienced one of the worst US outbreaks.
There have also been significant outbreaks in countries such as Singapore, despite its hot and muggy climate.
US President Donald Trump leapt upon the results to claim justification for statements earlier this year in which he said he believed the virus would go away as temperatures increase in April.
“I think a lot of people are going to go outside all of a sudden,” Trump said. “I hope people enjoy the sun and if it has an impact, that’s great.”
In February Trump said: “Looks like by April, you know, in theory, when it gets a little warmer, it miraculously goes away.”
The briefing featured a series of bemusing encounters as Trump asked medical advisers whether ultra-violet rays could be applied to the human body, or some form of internal disinfectant used, to cure the disease.
“Then I see the disinfectant, where it knocks it out in a minute, one minute, and is there a way we can do something like that by injection inside, or almost a cleaning?” Trump asked Bryan from Homeland Security.
He then asked Deborah Birx, the physician co-ordinating the White House’s coronavirus taskforce: “I would like you to speak to the medical doctors to see if there’s any way you can apply light and heat to cure. You know? If you could. And maybe you can, maybe you can’t.”
Birx said she had not seen any evidence that heat or UV rays could be used as a treatment for the virus.
Health experts immediately warned that sunlight was not a “miracle cure” for COVID-19 and that people should not try to treat it by tanning – especially given the risks of developing skin cancer.
On Friday, China announced it donated a further $US30 million ($47 million) to the World Health Organisation following Donald Trump’s decision to halt funding, amid concerns the UN agency is too “China-centric”.
Chinese Foreign Ministry spokesman Geng Shuang said the extra funds would help the WHO contain the virus and support developing countries in improving their public health systems.
“At this critical moment, support for WHO helps to strengthen multilateralism and the UN,” Shuang said.
Matthew Knott is North America correspondent for The Sydney Morning Herald and The Age.