Modelling the potential public health impact of different vaccination strategies with an omicron-adapted bivalent vaccine in Thailand

ABSTRACT

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 has continuously evolved, requiring the development of adapted vaccines. This study estimated the impact of the introduction and increased coverage of an Omicron-adapted bivalent booster vaccine in Thailand.

Research Design and Methods

The outcomes of booster vaccination with an Omicron-adapted bivalent vaccine versus no booster vaccination were estimated using a combined cohort Markov decision tree model. The population was stratified into high- and standard-risk subpopulations. Using age-specific inputs informed by 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 97,596 cases 36,578 hospitalizations, 903 deaths, THB 3,119 million in direct medical costs, and THB 10,589 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 (95%), hospitalizations (512%), infections (782%), direct costs (550%), and indirect costs (687%) compared to the base case.

Conclusions

Broader vaccination with an Omicron-adapted bivalent booster vaccine could have significant public health and economic benefits in Thailand.

KEYWORDS:

• Bivalent booster vaccine
• COVID-19
• Omicron
• Omicron-adapted vaccine
• SARS-CoV-2
• Thailand

Declaration of interest

K Thakkar, J Spinardi, MH Kyaw, J Yang, E Ozbilgili, 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. S Punrin has previously received speaker honoraria from Pfizer. Medical writing and editorial support was provided by Dr. Ruth Sharf-Williams at Evidera and was funded by Pfizer. The authors have no 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 an honorarium 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 Dr. Ruangwit Thamaree, Vaccines Medical Lead, Pfizer Thailand for his support. Assistance with model conceptualization and development and input collection was provided by Solene De Boisvilliers and Paul Lozowicki (Evidera). Medical writing was provided by Dr. Ruth Sharf-Williams (Evidera) and was funded by Pfizer, Inc.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14760584.2023.2265460.

Additional information

Funding

This paper was funded by Pfizer.