HBV breakthrough

Following the SARS breakthrough, Li said he was eager to find another area of research closely related to social development and health.

The hepatitis B virus, which attacks the liver and can cause diseases such as cancer and cirrhosis, came into his sights.

The World Health Organization estimated that 257 million people were living with chronic HBV infections in 2015 and about 887,000 people died of the virus that year.

The virus itself was discovered by Nobel laureate Baruch Blumberg in the 1960s, leading to the development of targeted blood tests and vaccines in the early 1970s.

But global scientists were unable to locate the receptor for the virus on human cells for more than four decades. Existing treatment does not cure the disease and most patients must take medication.

"To put it simply, the scale of hard work in regards to pinpointing the HBV receptor was at least twice what I encountered when studying SARS," Li said.

He also has a personal connection with the suffering inflicted by HBV infections.

When he was an undergraduate student at the Lanzhou Medical College in Gansu province he interned at the infectious diseases department of a local hospital, where he witnessed the agony and frustration of many HBV patients.

"Doctors aspiring to address issues of patients are usually constrained by limited medical knowledge and treatment options. The solution lies in boosting basic research and medical science," Li said.

In China, both the incidences and death rates of viral hepatitis－of which HBV account for the majority－rank among the highest of all infectious illnesses, according to the National Health Commission.

After completing his studies in the United States, Li returned to China in October 2007. He assembled a new team at the National Institute of Biological Sciences in Beijing, and set about looking for "the gate" through which HBV invades the human body.

"I was not sure if or when my team would find it," he said, adding the "thrill of uncertainties" made fundamental research "fun".

The breakthrough came on the evening of Jan 7, 2012, when the team found a protein that was highly likely to be the receptor.

They conducted more laboratory tests in the following months to collect new data and validate their results.

In November 2012, Li and his team finally published their research in the scientific journal Elife－one of the papers the team had released in five years.

Studying results not being published in a scientific journal can frustrate some researchers, but Li believes only worthwhile findings that push the frontiers of science should be published.

"Papers are important as they explain new observations and thinking. Our time and attention should be devoted to publishing papers at critical points of research, rather than pumping out one for every single phase," he said.