Singapore’s National Centre for Infectious Diseases (NCID) officially opened its doors in September 2019 – just months ahead of the start of the COVID-19 pandemic that is still sweeping the world. At its helm is Leo Yee Sin, a veteran of Singapore’s battles with infectious diseases such as Nipah, SARS, pandemic influenza, Zika, dengue, and Monkeypox.

In January 2020, Yee Sin, who is NCID’s Executive Director, and her team started to watch very closely what was happening in Wuhan, China. When they learnt there was potential human-to-human transmission, they knew Singapore would not be spared.

The hints that it could be another coronavirus prompted the National Public Health Laboratory (NPHL) at NCID to prepare a pan-corona virus PCR (polymerase chain reaction) diagnostic tool. When the new virus, SARS-CoV-2, was confirmed as the causative agent and the virus RNA (ribonucleic acid) sequence was released by China, NPHL designed a SARS-CoV-2 PCR assay and optimised the test over the next week. The test was ready when the first case turned up in Singapore.

Meanwhile, the clinical, nursing, and allied health teams raced to prepare for the potential influx of patients. Drills and simulations of outbreaks were conducted regularly. Research is essential to deal with a new emerging infectious disease and NCID set up a National COVID-19 Research Workgroup.

When the first case of COVID-19 was confirmed in Singapore on 23 January 2020, “all these things were ready” and “we were even able to enrol the first case into our cohort study”, Yee-Sin told British medical journal The Lancet. This readiness helped to keep Singapore’s initial COVID-19 fatality rate low.

When the Delta variant of SARS-CoV-2 emerged in early 2021, NCID had to deal with a new set of challenges. Delta was much more transmissible, and far more likely to cause severe disease especially among the elderly and the unvaccinated. Adjustments had to be made, and the adjustments continued as other variants appeared.

“The COVID-19 pandemic was a humbling experience,” Yee Sin told medical publication Medicus in 2021. “Initially, we thought it would be manageable and easy to overcome, but it was not. I think there is much we can learn from the virus to prepare us for future pandemics.”

Yee Sin has been battling infectious diseases since 1989, when she started specialising in the field. In 1992, she worked as a clinical fellow in Los Angeles, where half of her workload consisted of HIV cases.

When she returned to Singapore, she decided to specialise in HIV medicine. It was then still a taboo topic. “There was no effective treatment, we struggled a lot with opportunistic infections”, she told The Lancet. “The worst part was that at that point, there was no subsidy provided for HIV patients in Singapore.”

In 1995, Yee Sin established the first HIV programme in Singapore, and in 1997 she set up the Patient Care Centre at the Communicable Disease Centre. She raised funds to help HIV patients with the high cost of their medication, and she worked hard to get policymakers to see the importance of HIV treatment. Today HIV is no longer the fearful and isolating disease it used to be and, with advances in medical research and treatment, a person living with HIV can live life no differently from anyone else.

In 1999, the Nipah virus hit Singapore, giving Yee Sin her first frontline experience with emerging novel infectious diseases. Then came SARS and the other outbreaks, and as Yee Sin and her team grappled with each new threat to public health in Singapore, her reputation as a leader in Singapore’s fight against infectious diseases grew.

In 2020, Yee Sin was named by the BBC as one of the world’s top 100 Women because of her work in tackling COVID-19. She was the 4th Singaporean woman to be included in the broadcaster’s annual list. In 2003, she was awarded the Public Service Star for her work in combating SARS. She has also received the Public Administration Medal twice – the Bronze in 2012 and the Silver in 2020.

Yee Sin, who is also a professor at the National University of Singapore, has published more than 300 scientific papers. In December 2021, she turned her hand to a different kind of publication – a book for children about COVID-19. Titled My Coronavirus Story, the book is written in rhyme and the illustration are by children.

She decided to write the book, she explained, because “I saw first-hand what it means to be on the frontline dealing with COVID-19, and I was inspired to translate my observations into the perspective of the young – to explain the virus in a simple manner, describe how it has impacted their lives and help them see the way forward.”

Singapore’s National Centre for Infectious Diseases (NCID) officially opened its doors in September 2019 – just months ahead of the start of the COVID-19 pandemic that is still sweeping the world. At its helm is Leo Yee Sin, a veteran of Singapore’s battles with infectious diseases such as Nipah, SARS, pandemic influenza, Zika, dengue, and Monkeypox.

In January 2020, Yee Sin, who is NCID’s Executive Director, and her team started to watch very closely what was happening in Wuhan, China. When they learnt there was potential human-to-human transmission, they knew Singapore would not be spared.

The hints that it could be another coronavirus prompted the National Public Health Laboratory (NPHL) at NCID to prepare a pan-corona virus PCR (polymerase chain reaction) diagnostic tool. When the new virus, SARS-CoV-2, was confirmed as the causative agent and the virus RNA (ribonucleic acid) sequence was released by China, NPHL designed a SARS-CoV-2 PCR assay and optimised the test over the next week. The test was ready when the first case turned up in Singapore.

Meanwhile, the clinical, nursing, and allied health teams raced to prepare for the potential influx of patients. Drills and simulations of outbreaks were conducted regularly. Research is essential to deal with a new emerging infectious disease and NCID set up a National COVID-19 Research Workgroup.

When the first case of COVID-19 was confirmed in Singapore on 23 January 2020, “all these things were ready” and “we were even able to enrol the first case into our cohort study”, Yee-Sin told British medical journal The Lancet. This readiness helped to keep Singapore’s initial COVID-19 fatality rate low.

When the Delta variant of SARS-CoV-2 emerged in early 2021, NCID had to deal with a new set of challenges. Delta was much more transmissible, and far more likely to cause severe disease especially among the elderly and the unvaccinated. Adjustments had to be made, and the adjustments continued as other variants appeared.

“The COVID-19 pandemic was a humbling experience,” Yee Sin told medical publication Medicus in 2021. “Initially, we thought it would be manageable and easy to overcome, but it was not. I think there is much we can learn from the virus to prepare us for future pandemics.”

Yee Sin has been battling infectious diseases since 1989, when she started specialising in the field. In 1992, she worked as a clinical fellow in Los Angeles, where half of her workload consisted of HIV cases.

When she returned to Singapore, she decided to specialise in HIV medicine. It was then still a taboo topic. “There was no effective treatment, we struggled a lot with opportunistic infections”, she told The Lancet. “The worst part was that at that point, there was no subsidy provided for HIV patients in Singapore.”

In 1995, Yee Sin established the first HIV programme in Singapore, and in 1997 she set up the Patient Care Centre at the Communicable Disease Centre. She raised funds to help HIV patients with the high cost of their medication, and she worked hard to get policymakers to see the importance of HIV treatment. Today HIV is no longer the fearful and isolating disease it used to be and, with advances in medical research and treatment, a person living with HIV can live life no differently from anyone else.

In 1999, the Nipah virus hit Singapore, giving Yee Sin her first frontline experience with emerging novel infectious diseases. Then came SARS and the other outbreaks, and as Yee Sin and her team grappled with each new threat to public health in Singapore, her reputation as a leader in Singapore’s fight against infectious diseases grew.

In 2020, Yee Sin was named by the BBC as one of the world’s top 100 Women because of her work in tackling COVID-19. She was the 4th Singaporean woman to be included in the broadcaster’s annual list. In 2003, she was awarded the Public Service Star for her work in combating SARS. She has also received the Public Administration Medal twice – the Bronze in 2012 and the Silver in 2020.

Yee Sin, who is also a professor at the National University of Singapore, has published more than 300 scientific papers. In December 2021, she turned her hand to a different kind of publication – a book for children about COVID-19. Titled My Coronavirus Story, the book is written in rhyme and the illustration are by children.

She decided to write the book, she explained, because “I saw first-hand what it means to be on the frontline dealing with COVID-19, and I was inspired to translate my observations into the perspective of the young – to explain the virus in a simple manner, describe how it has impacted their lives and help them see the way forward.”