Studies show a very high possibility that COVID-19 first emerged outside China, said Zeng Guang, the chief epidemiologist at China's Center for Disease Control and Prevention (CDC). 

Just because China discovered and reported it first to the world does not mean the country is where the virus originated, he said at a medical forum at the third China International Import and Export Forum (CIIE) in Shanghai last week.  

He said an important reason China discovered the epidemic first is that the country experienced SARS in 2003 and has since established a reporting system for pneumonia with unknown causes.

But that has made China easily misunderstood by other countries, he said. 

The expert also explained that, normally, the origins of most epidemics remain unclear, and only in very few cases can scientists solve the mystery. That's because viruses that cause infectious diseases usually evolve in nature for many years and get passed on to many different animals before they reach humans and start spreading.  

Scientists generally believe that instead of focusing on tracing the origin, people should pay attention to detecting a new epidemic quickly and mapping out public health policies to cut off its transmission and work on the treatment, Zeng said. 

He added that there will be new infectious diseases in the future, and it is especially important to strengthen public health systems.