During the SARS outbreak, he conducted research on SARS treatment and vaccine.[5] In 2006, he was awarded US$1.9 million by the Grand Challenges In Global Health initiative of the Bill & Melinda Gates Foundation, for his research on vaccines for HIV and hepatitis C.[4] He became Director of Peking University's Institute of Stem Cell Research in 2013 and was appointed the Boya Chair Professor in 2016.[2][6]