In Conversation With

Professor Leo Yee Sin  

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With the emergence of the Delta variant early this year, the SARS-CoV-2 virus redoubled its efforts to gain the upper hand as it attempts to fuel yet another wave of infections in the community. Having weathered the first assault from the original—or ancestral—strain last year, the National Centre for Infectious Diseases (NCID) is digging even deeper to protect the people of Singapore against this invisible enemy. Its executive director, Professor Leo Yee Sin, speaks to MEDICUS to share her reflections on the pandemic, the issues at stake and the importance of collaboration.

MEDICUS: NCID has just celebrated its second anniversary as a new entity. Looking back, can you share how the pandemic has affected NCID?

Leo Yee Sin: Even before we were officially opened, NCID had to tackle outbreaks of monkey pox and measles. Then, barely four months after celebrating NCID’s official opening, we had to respond to COVID-19 in January 2020—so we couldn’t really think of anything other than COVID that year. In fact, for many of us, 2020 was a year of relative emptiness.  

This year, most of us were looking forward to a more pleasant year ahead. We thought we would have a period of relative calm. Indeed, it came—and went—very quickly.

With the Delta variant’s arrival in April, we were faced with a different set of challenges. At first, we thought this variant shouldn’t be much different from the ancestral strain. But as we started looking at the data we had collected, we realised that although they are both SARS-CoV-2, this variant’s behaviour was very different. We know now that the Delta variant tends to exist in higher quantities in excretions from the respiratory system, so we had to anticipate that it will have a very high capability of transmission. But we still don’t have all the answers.

MEDICUS: How has this finding affected your thoughts on vaccine strategy?

Leo Yee Sin: I think there are two main considerations here: Do I want to just have vaccines that prevent severe illness? Or do I want to have vaccines that prevent infection? If I go for the first route, which is to use vaccines to protect the at-risk populations and reduce severe disease, then the target will be the vulnerable populations. But to protect against infection, then we need a much, much wider ring. We need to bring in the younger people, and if vaccines for children become available, that may be another strategy to consider. But to me, if I can prevent infection, I can naturally prevent severe illness.

But any vaccination strategy also needs to take into consideration our social behaviour—our social fabric, social interactions and society in general. In a country where the vulnerable population can be well protected from the rest, protection against severe illness may be sufficient. However, in Singapore and other Asian countries, that really is not the case. Many of us live as a family with three generations, so it is not possible to isolate your older folks from the young people who are going out and may potentially bring the virus back home. We have to consider these factors and, ultimately, no one decision is good for everybody. We just need to find the best solution for each individual and country.

MEDICUS: How can we brace ourselves for other unexpected developments that may come our way?

Leo Yee Sin: If you look at SARS-CoV-2, the virus has evolved very fast. But seeing how we have adapted every step of the way, I think we are prepared. We have been adjusting our safe management measures. To those, we added the element of prevention and protection by rolling out vaccines, with many new therapeutics that are being developed. Now, it is only a matter of time before new medications are made available.

And we are also taking our preparations one step further with our new national Programme for Epidemic Preparedness and Response (PREPARE) by putting together key elements that will enable us to strengthen our capabilities to respond better to future outbreaks.

MEDICUS: We have come a long way since the pandemic broke, attaining an 80 per cent vaccination threshold for the population as of end August. Given the fast rate at which pandemic-related information is evolving, how can we then communicate the unexpected effectively to the general public?

Leo Yee Sin: You have to expect yourself to be surprised. This was a new virus and our initial decisions were based on incomplete data. For example, the 80 per cent threshold was set based on our best judgement from an understanding of the virus and the data that was available at that point. But given the fluidity of the situation, we need to continue to gather more data to understand if we have made the best decision and adjust our course if necessary. But communicating this to the public has been challenging. We have had to rely on the trust that we have built with the public and have to continue to communicate the science in an open and transparent manner so that we get their support.

MEDICUS: This is not the first emerging diseases outbreak that you’ve personally experienced. What are the biggest take home lessons for you?

Leo Yee Sin: First of all, flexibility. We need to keep an open mind and continue to ask questions. For example, are the variants all similar in nature? And if not, what are the changes that we need to know about among the different variant of concerns or even variants of interest? You may think you know everything about the virus, but it could be all wrong as our experience with the Delta variant has shown us.

Second, the scalability of our health services. The size of COVID-19 outbreak was certainly much bigger than previous epidemics or pandemics that we encountered, so we need to ensure that we are able to scale up our services to meet the demand.

Third, the need to create a knowledge database. We need to gather evidence to improve our management of the pandemic and to support evidence-based policy decision-making.

And last, the importance of networking and collaboration. Strengthening our connections with partners within the region and globally will enable us to maintain a state of preparedness, whether it is against COVID-19 or new strains of SARS-CoV-2 that may emerge.

MEDICUS: How has the COVID-19 pandemic affected the approach that NCID will adopt for future pandemics caused by a Pathogen X?

Leo Yee Sin: For most of us, the COVID-19 pandemic was a humbling experience. 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.

We will continue to be humble, be flexible—ready to change the course of action—and inquisitive, always keeping an open mind. Then, the next important step would involve forming meaningful connection, connecting the “dots”—connecting with our own community in Singapore, connecting with our counterparts regionally and connecting with international bodies to fight the pandemic collectively.

MEDICUS: Could you share NCID’s strategic goals for the year ahead?

Leo Yee Sin: We will focus on a few key components, such as clinical care, public health, research and community engagement. In terms of clinical care, we hope to continue to advance and provide the best of care to patients who are suffering from not just SARS-CoV-2 but other infectious diseases as well and provide guidance in areas where we can standardise medical treatment.

We also have plans to develop our expertise in public health further with strategies targeted at making sense of data collected from epidemiological studies. Part of this includes our active participation in the national R&D programme, PREPARE, in which data analysis and data science are key. Having the ability to integrate and extract data from multiple sources would provide us with answers in real-time, which would enable us to analyse strategic information that is required for evidence-based policy decision-making.

Our professional arm will continue to focus on our research efforts while our small community branch will explore effective ways of transmitting key messages to the community and getting the sensing from the community back to us. Lastly, we also hope to initiate bilateral and multilateral conversations among our partners in the biomedical science ecosystem.

MEDICUS: You mentioned collaboration as a key aspect when sharing your reflections for the year. How have NCID and Duke-NUS been able to make greater things happen together?

Leo Yee Sin: We put together a multi-disciplinary research network with Professor Wang Linfa a day before the first COVID-19 case was detected in Singapore. In fact, he was the key collaborator and driver who has been working with us. Because of our network, we were able to collect specimens and share them across many different institutions, be it A*STAR, Duke-NUS or other research partners enabling everyone to focus very deeply on their area of research, which has led to a number of successes. For example, the cPass™ kit, which Linfa’s team has developed that is widely used in COVID-19 investigations today.

My colleagues have also been working closely with Professor Antonio Bertoletti’s team looking at cellular immunity against SARS-CoV-2 as well as the Laboratory of Virus Evolution led by Professor Gavin Smith on genome analysis. I would say that we should not just stop there. We are happy to expand our network and further explore potential areas of research collaboration with Duke-NUS as well as many other partners in Singapore and beyond.

MEDICUS: Having worked in outbreak mode for more than 22 months, how do you re-charge and keep going?

Having battled SARS-CoV-2 for 22 months and counting, I must stress that we do have a fatigued group of healthcare workers and individuals. At this moment, giving them the encouragement to ride through this wave is very important. Community support and encouragement has always been one of the very big morale boosters to healthcare workers, and this goes hand in hand with providing them brief periods of respite from work to recharge before facing the possible challenges ahead.

As for myself, I like to enjoy some quiet moments by taking long walks in green open spaces alone or with my family. Walking helps me to calm down and also gives me the time to think and strategise.

MEDICUS: Thank you for sharing your valuable insights.

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