On Thursday, a U.S. official said that the deadly COVID-19 appears to weaken more quickly when exposed to sunlight, heat, and humidity, alleging that the pandemic could become less contagious in summer months.
Government researches in the United States have determined that the coronavirus survives best indoors and in dry conditions, and loses its potency when exposed to higher temperatures and humidity-- especially when in sunlight said William Bryan, acting head of the U.S. Department of Homeland Security’s Science and Technology Directorate.
“The virus dies quickest in the presence of direct sunlight,” he told a White House news briefing.
This research could raise expectations of the highly infectious virus behaving just like the less fatal respiratory diseases like influenza, which typically are less contagious in warm weather.
However, despite these findings, the virus has proven to thrive in countries with hot and humid weather like Singapore and India.
Previously, US President Donald Trump, throwing caution the wind had said that maybe the deadly virus could go away with heat and light-- comments for which he faced backlash. This time, however, he warned that these findings should be interpreted cautiously, but also claimed vindication for previously suggesting that the coronavirus might recede in summer.
“I once mentioned that maybe it does go away with heat and light. And people didn’t like that statement that much,” he said at the briefing.
Bryan claimed that on nonporous surfaces like stainless steel, the novel virus took up to 18 hours to lose half its strength in a dark, low-humidity environment. On the other hand, in humid environments, that half-life dropped to six hours, and when the virus was exposed to high humidity and sunlight, the half-life dropped to two minutes, he said.
Researchers found a similar effect with the coronavirus that was suspended in the air - simulating the coughing or sneezing that often spreads the disease. In a dark room, the virus maintained half its strength for an hour. But when exposed to sunlight, it lost half its strength in 90 seconds, Bryan said.