Sunlight, heat and humidity weaken coronavirus: US official

The coronavirus seems to weaken more instantly when exposed to sunlight, heat and humidity; the U.S. official said on Thursday in a potential sign that the pandemic could lessen spreading in summer months.

U.S. government researchers have determined that the virus survives best indoors and in dry conditions, and loses power when temperatures and humidity rise - and particularly when it's exposed to sunlight, said William Bryan, acting head of the U.S. Department of Homeland Security's Science and Technology Directorate.

"The virus dies most immediate within the presence of direct sunlight," he told a White House news briefing.

The findings could bolster hopes that the coronavirus will simulate the behaviour of other respiratory diseases like influenza, which generally are less deadly in warm weather.

But the coronavirus has also proven deadly in warm-weather places like Singapore, raising broader questions on the impact of environmental factors.

President Donald Trump said the findings should be interpreted cautiously but also claimed vindication for previously suggesting that the coronavirus might recede in summer.

"I once mentioned that perhaps it does get away with heat and light. And people didn't like that statement that much," he said at the briefing.

Sixteen U.S. states are setting plans to restart their economies and reduce regulations designed to reduce the spread of the pandemic. Georgia and South Carolina are providing some businesses to reopen in the week. In essence, a move that health authorities say could lead on to more deaths because they are doing not have enough tests to assess how many people are infected.

Trump's administration says states should wait until they need evidence that infection rates have dropped steadily for two weeks.

Vice President Mike Pence said states should allow hospitals and other medical facilities to resume elective surgeries, a vital source of revenue that some governors have banned to stay hospitals clear for coronavirus patients.

Trump said Americans must maintain social distancing into early summer, although some states were showing signs of progress.

Trump has encouraged protests against social-distancing restrictions in some states. But he criticized Georgia Governor Brian Kemp, a fellow Republican, for moving too quickly.

"I want the people in Georgia to be safe, and that I don't want this thing to flare up because you're deciding to try and do something that's not within the guidelines," he said.

More than 874,000 people within the U.S. are known to possess been infected, and over 49,600 have died of COVID-19, the highly contagious disease caused by the new coronavirus, in step with a Reuters tally.