The Department of Social and Preventive Medicine is delighted to extend our warmest congratulations to Dr Lim Say Hiang on the successful defence of her Doctor of Public Health thesis entitled “Prevalence, Factors and Effect of Long COVID on Work Productivity Among Healthcare Workers at Universiti Malaya Medical Centre.”
This achievement marks not only the culmination of years of rigorous scholarship but also a significant contribution to occupational and public health research in Malaysia and beyond.
Summary of the Thesis
Dr Lim conducted a robust retrospective cohort study among 976 healthcare workers (HCWs) at Universiti Malaya Medical Centre to investigate the prevalence, associated factors, and consequences of Long COVID. Defined as the persistence of COVID-19 symptoms beyond four weeks, Long COVID was found to affect 49.2% of HCWs in the study population, a strikingly high prevalence. The most commonly reported symptoms were fatigue (25.3%) and cough (23.7%).
His research identified several significant predictors of Long COVID:
- Female sex
- Recurrent COVID-19 infection (two or more episodes)
- Greater severity of initial infection (Category 2 and ≥ Category 3)
Beyond prevalence, Dr Lim’s work moved decisively into impact analysis. Healthcare workers with Long COVID experienced:
- Lower scores across all eight domains of Health-Related Quality of Life (HRQoL)
- Significantly poorer Physical Component Summary (PCS) and Mental Component Summary (MCS) scores
- Increased anxiety and depression levels
- Lower absolute presenteeism
- Higher annual monetary loss due to reduced work performance
The findings paint a comprehensive picture: Long COVID is not merely a lingering clinical condition; it is a multidimensional occupational health challenge that affects productivity, mental health, and the resilience of the healthcare system.
Highlight of Achievements
Dr Lim’s doctoral journey is distinguished not only by a well-executed dissertation but also by meaningful scholarly outputs.
He has successfully published impactful research, including:
- Effect of Long COVID on Work Performance and Annual Monetary Loss Among Infected Health Care Workers at a Tertiary Hospital in Malaysia
– Demonstrating significantly higher annual monetary loss (MYR 10,866.61) among HCWs with Long COVID compared to those without. - Prevalence and Predictors of Post-Acute COVID Syndrome Among Infected Healthcare Workers at University Malaya Medical Centre
– Reporting a PACS prevalence of 50.7% and identifying key risk factors such as female sex, asthma, and COVID-19 severity.
Completing a DrPH while producing high-quality publications reflects intellectual resilience, research leadership, and unwavering commitment.
Contribution to Public Health
Dr Lim’s work arrives at a critical juncture in global health recovery. Healthcare workers stood at the frontline of the COVID-19 pandemic. Yet, as his research reveals, the long-term occupational consequences remain substantial and under-recognised. His study contributes to public health in several important ways:
- Evidence for Policy Reform – Demonstrating the economic burden of presenteeism provides tangible data for hospital administrators and policymakers.
- Workplace Health Advocacy – The findings support structured workplace accommodations and rehabilitation programmes.
- Mental Health Integration – By linking Long COVID with anxiety and depression, her research reinforces the need for integrated occupational mental health services.
- Surveillance and Preparedness – Her call for longitudinal monitoring strengthens preparedness for future pandemics.
In short, this work bridges epidemiology, occupational medicine, health economics, and mental health, embodying doctoral-level public health scholarship.
Acknowledgement
We wish to acknowledge the invaluable guidance and mentorship provided by Dr Lim Say Hiang’s supervisors, Professor Dr. Rafdzah Ahmad Zaki and Dr. Lim Yin Cheng, whose expertise and support were instrumental in the completion of her thesis.
We extend our sincere gratitude to Professor Dr. Naesinee Chaiear, Department of Community, Family and Occupational Medicine, Faculty of Medicine, Khon Kaen University, Thailand, and Dr. Bala Murali a/l Sundram, Internal Examiner.
We would also like to thank the Committee of Examiners for their thorough evaluation and insightful feedback, including Professor Dr. Jamunarani a/p S Vadivelu, the Chairperson of the viva voce session; Assoc. Prof. Dr. Anand a/l Sanmugam, Deputy Dean (Postgraduate Studies), Faculty of Medicine, Universiti Malaya; and Professor Dr. Victor Hoe Chee Wai Abdullah, Head of Department, Department of Social and Preventive Medicine.
Congratulations and Future Expectations
Dr Lim Say Hiang, today you join the community of public health leaders who do more than generate data; you generate impact. Your research provides timely, policy-relevant, and actionable insights that can shape institutional strategies, occupational health frameworks, and national preparedness planning.
As you move forward, we look forward to seeing:
- Expanded longitudinal research on Long COVID
- Regional and international collaborations
- Policy translation at ministerial and institutional levels
- Continued advocacy for healthcare worker wellbeing
The Doctor of Public Health degree is not merely a title; it is a responsibility to lead, to question, and to serve.
Heartiest congratulations, Dr Lim Say Hiang. Your scholarship strengthens our healthcare workforce, informs our policies, and advances the science of public health.
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