On Jan. 15, it seemed like the U.S. and China had avoided a quick descent into a new Cold War.

In Washington, U.S. President Donald Trump declared that "our relationship with China is the best it’s ever been” while signing a preliminary trade deal that "unifies the countries.” The pact between Trump and China’s Xi Jinping raised hopes that the world’s predominant superpower could peacefully resolve differences with a rising China.

That same day, health officials in the central Chinese city of Wuhan acknowledged that they couldn’t rule out human-to-human transmission of a mysterious new pneumonia that had already sickened 41 people. A man who had visited Wuhan also arrived home in Washington state carrying the deadly pathogen — the first confirmed U.S. case of the disease that would become known as COVID-19.