Curbing COVID-19 through border controls and restricted entry

Thought LeadersDr. Sheng-Chia ChungSenior Research AssociateUniversity College London

In our latest interview, we spoke to epidemiologist Dr. Sheng-Chia Chung about her latest research that investigated curbing COVID-19 transmission through border controls and restricted entry.

Please could you introduce yourself and tell us what inspired your research into COVID-19?

I am an epidemiologist originally from Taiwan. When coronavirus returned in 2019, it is natural for an epidemiologist to contribute to the COVID-19 response.

Many research efforts have been dedicated to stopping the spread of the SARS-CoV-2 virus. Why is it important to ensure we have effective measures in place to stop its transmission?

With effective measures in place, many of the COVID-19 mortality and morbidity can be prevented.

The goal of effective measures is to interrupt the transmission of SARS-CoV-2, preventing the virus from spreading to susceptible and vulnerable individuals, especially those with a higher risk of developing severe symptoms or death of COVID-19.

Spread of COVID-19

Spread of COVID-19. Image Credit: ETAJOE/

The find, test, trace, isolate, and support (FTTIS) system has been adopted by many countries to help control the spread of the virus, however, silent transmission is poorly understood. Why is this and why is it important to recognize the unique characteristics of the SARS-CoV-2 virus?

One of the main reasons would be the transmission by presymptomatic and asymptomatic individuals. Effective contact tracing and adequate testing could address this issue.

The emerging SARS-Cov-2 variants with a higher attack rate are the other concern. It is thus important to monitor and update our understanding of the evolution of SARS-CoV-2 and its impact on the susceptibility of the population.    

Can you describe how you carried out your latest research into COVID-19 transmission? What did your results show?

Our research reviewed studies on measures to prevent SARS-Cov-2 transmission during the rapid response phase of the pandemic. We found that a successful find, test, trace, isolation, and support program (FTTIS) for COVID-19 requires:

Case finding via measures such as border controls, restricted entry, and inbound traveler quarantine, combined with testing high-risk populations and contacts of diagnosed COVID-19 patients. Timely and repeated testing may be necessary to minimize false-negative results. Trace digital tools can aid in outbreak investigation, contact tracing, and monitoring compliance with self-isolation. An individual infected by SARS-CoV-2 can actively shed the virus 3 weeks or longer after symptoms onset.

A 2-week quarantine period with an extension when required could interrupt further transmission. Support provides adequate supplies or allowance for individuals during self-isolation. A successful FTTIS requires seamless integration of all the components and the ability to integrate vulnerable populations or ethnic minorities.

A timely and effective FTTIS also facilitates public trust that is fundamental in the joint COVID-19 response in the population, as it relies on individuals to voluntarily provide their information and adhere to disease control regulations.


Quarantine. Image Credit: Natasa Adzic/

How could your research also be applied to future pandemics?

Our research identifies determinants of successful FTTIS strategies for COVID-19 response. We have seen that countries going through SARS in 2003 and had experiences applying FTTIS for coronavirus outbreaks have less incidence and mortality because of COVID-19.

As the COVID-19 pandemic continues, the results from the current research can aid populations to manage the current and prepare for future pandemics.

What can countries and governments do now to help prevent the spread of COVID-19? Do you believe that with restricted entry and quarantine, we could potentially reduce the spread of the virus?

Countries and governments can combine effective FTTIS strategies with vaccination programs to prevent the spread of SARS-CoV-2.

Restricted entry and quarantine is the first line of protection preventing the virus from entering a susceptible population and spreading.  It should be done properly, with the streamlined process of testing, triage, separate pathways, referral, transport, quarantine locations, and follow-up. Each step requires proper infectious control and management.

The COVID-19 pandemic has also taught us the importance of working together to achieve goals and make quick scientific progress. How important was collaboration to your research?

The research was only possible with the selfless contribution of all collaborators, from different countries and various disciplines (scientist, clinicians, urban designer, legal practitioner, and engineer), driven by the common goal for a better COVID-19 response.

COVID-19 pandemic has made a lasting impact on all aspects of human societies worldwide. To overcome the challenges have COVID-19 laid out for all of us, worldwide we need to join together to find sensible solutions collectively.

What are the next steps in your research?

I am currently working on a case study of COVID-19 response in Taiwan.

Where can readers find more information?

The full research article can be found here:

About Dr. Sheng-Chia Chung

Sheng-Chia Chung is currently a senior research associate at the University College London, an epidemiologist, and an analyst in the fields of health informatics, epidemiology, and international comparisons.Dr. Sheng-Chia Chung

More about the research work of Sheng-Chia can be found at:

Emily Henderson

Written by

Emily Henderson

During her time at AZoNetwork, Emily has interviewed over 300 leading experts in all areas of science and healthcare including the World Health Organization and the United Nations. She loves being at the forefront of exciting new research and sharing science stories with thought leaders all over the world.


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