Modelling the Potential Public Health Impact of Different COVID-19 Vaccination Strategies with an Adapted Vaccine in Singapore

ABSTRACT

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 has been a dynamically changing virus, requiring the development of adapted vaccines. This study estimated the potential public health impact alternative vaccination strategies for COVID-19 in Singapore.

Research Design and Methods

The outcomes of alternative vaccination strategies with a future adapted vaccine were estimated using a combined Markov decision tree model. The population was stratified by high- and standard-risk. Using age-specific inputs informed by local surveillance data and published sources, the model estimated health (case numbers, hospitalizations, and deaths) and economic (medical costs and productivity losses) outcomes in different age and risk subpopulations.

Results

Booster vaccination in only the elderly and high-risk subpopulation was estimated to avert 278,614 cases 21,558 hospitalizations, 239 deaths, Singapore dollars (SGD) 277 million in direct medical costs, and SGD 684 million in indirect medical costs. These benefits increased as vaccination was expanded to other subpopulations. Increasing the booster vaccination coverage to 75% of the standard-risk population averted more deaths (3%), hospitalizations (29%), infections (145%), direct costs (90%), and indirect costs (192%) compared to the base case.

Conclusions

Broader vaccination strategies using an adapted booster vaccine could have substantial public health and economic impact in Singapore.

KEYWORDS:

• Booster vaccine
• COVID-19
• Omicron-adapted vaccine
• SARS-CoV-2
• Singapore

Declaration of interest

K Thakkar, J Spinardi, MH Kyaw, J Yang, E Ozbilgili, B Taysi, and C Mendoza are employees of Pfizer and may hold stock or stock options of Pfizer. J Dodd and B Yarnoff are employees of Evidera, which received financial support from Pfizer in connection with the study and the development of this manuscript. Medical writing and editorial support was provided by Dr. Ruth Sharf-Williams at Evidera and was funded by Pfizer. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or material discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have received honoraria for their review work. Peer reviewers on this manuscript have no other relevant financial or other relationships to disclose.

Author contributions

All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship for this article. All authors contributed to study conception and design, data acquisition, analysis, and interpretation, drafting and revising of the manuscript.

Acknowledgments

We would like to thank Ervin Cheong, Medical Scientific Specialist, Pfizer Singapore for his support. Assistance with model conceptualization and development and input collection was provided by Solene De Boisvilliers and Lucie Bouin (Evidera). Medical writing was provided by Dr. Ruth Sharf-Williams (Evidera) and was funded by Pfizer, Inc.

Supplemental Material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14760584.2023.2290931

Additional information

Funding

This paper was funded by Pfizer.