Professor Leo Yee Sin is the executive director of the National Centre for Infectious Diseases, Singapore.

As an adult infectious disease specialist, Prof Leo has led her team through multiple outbreaks in Singapore. These include Nipah in 1999, SARS in 2003, the pandemic influenza in 2009, Zika in 2016 and multiple surges of dengue fever. Most recently, she successfully managed Singapore's first imported case of monkeypox in May 2019. Her current priority is in the fight against Covid-19.

Prof Leo has published close to 400 peer-reviewed scientific papers. Due to her experience and expertise in outbreak management, she is frequently called upon as an adviser and speaker at both national and international conferences. She has served in multiple World Health Organization work groups on outbreak management, and as an international expert in scientific and research bodies.

Apart from her clinical and administrative duties, she is also heavily involved in research and teaching. Topics of her research include dengue, influenza, emerging infections, HIV and Covid-19.

She has won many awards including the most prestigious Public Service Star in recognition of her outstanding battle against SARS in 2003 and two Public Administration Medals in 2012 and 2020.

In 2022, Prof Leo was inducted into the Singapore Women's Hall of Fame and conferred the title of Knight of the French Order of the Legion of Honour, by France’s Ambassador to Singapore Marc Abensour, on behalf of the President of the French Republic.