New medical reports from China have shown that people who have no symptoms and initially test negative for COVID-19 can still spread the virus.
It showed how a 20-year-old woman from Wuhan infected five relatives in the Chinese city of Anyang.
Published by the Journal of the American Medical Association, the study offered new evidence that the virus can spread asymptomatically.
It showed that "none of the patients had visited Wuhan or been in contact with any other people who had travelled to Wuhan" - except their 20-year-old relative.
So far, China has reported 76,288 cases, including 2,345 deaths.
Meanwhile, the WHO confirmed that more than 1,200 cases of the virus have been confirmed in 26 countries, with eight deaths.
US President Donald Trump will follow up his summit with Xi Jinping by taking the Chinese leader on Friday to the US National Archives, where they are expected to stress views about the history and direction of ties between their countries.
France will send troops and defence systems to Saudi Arabia to help protect the Red Sea port city of Yanbu, which is key for energy transport, French President Emmanuel Macron said on Thursday.
The United Nations Conference on Trade and Development (UNCTAD) warned that the Palestinian economy is currently facing “the most severe economic crisis recorded anywhere in the world", with an estimate $71.5 billion needed for recovery.
Prime Minister Benjamin Netanyahu mounted a forceful defence of Israel's actions in the region at the UN, seeking to counter growing international isolation ahead of elections he could lose, as dozens of delegates streamed out.
US President Donald Trump welcomed Chinese President Xi Jinping to the White House on Thursday for a lavish state summit expected to be heavy on symbolism but light on substance, with both leaders keen to showcase stable ties despite a host of thorny issues.