A recent research paper indicated that COVID-19 could have circulated in Italy in late 2019, weeks before it was formally identified in China, raising more questions about the origins of the virus.

Since the start of the COVID-19 pandemic, scientists from all over the world have been researching SARS-CoV-2, the virus that causes the disease. 

Through screening of past cases, tests on blood samples and even wastewater, multiple studies found the existence of the virus elsewhere before China reported its first case.

"These examples come from recent studies of scientists from around the world, which show that Wuhan might not have been the first place of SARS-CoV-2 inception," said Liang Wannian last month, team leader of the Chinese side of the joint expert team of World Health Organization (WHO)-convened global study of COVID-19 origins.

From January 14 to February 10, a total of 34 experts from the WHO and China jointly conducted a 28-day research in Wuhan. While concluding the so-called "lab leak" theory "extremely unlikely," they also recommended conducting further research around earlier cases globally.

Read more:

Timeline: China's cooperation with WHO on COVID-19 origins study

Graphics: Key questions addressed by WHO report on COVID-19 origins

COVID-19 origin: Virus origin-tracing should be conducted in multiple countries - Xinhua commentary