Impact of the COVID-19 vaccine booster strategy on vaccine protection: a pilot study of a military hospital in Taiwan

Yu-Li Wang; Shu-Tsai Cheng; Ching-Fen Shen; Shu-Wei Huang; Chao-Min Cheng

doi:10.7774/cevr.2023.12.4.337

Impact of the COVID-19 vaccine booster strategy on vaccine protection: a pilot study of a military hospital in Taiwan

Clin Exp Vaccine Res. 2023 Oct;12(4):337-345. doi: 10.7774/cevr.2023.12.4.337. Epub 2023 Oct 31.

Authors

Yu-Li Wang^{1

2

3}, Shu-Tsai Cheng³, Ching-Fen Shen⁴, Shu-Wei Huang^{5

6}, Chao-Min Cheng³

Affiliations

¹ Department of Emergent Room, Armed Force Hualien General Hospital, Hualien, Taiwan.
² International Intercollegiate Ph.D. Program, National Tsing Hua University, Hsinchu, Taiwan.
³ Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan.
⁴ Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
⁵ Department of Orthopedics, Taipei Municipal Wanfang Hospital, Taipei Medical University, Taipei, Taiwan.
⁶ Graduate Institute of Health and Biotechnology Law, Taipei Medical University, Taipei, Taiwan.

Abstract

Purpose: The global fight against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to widespread vaccination efforts, yet the optimal dosing schedule for SARS-CoV-2 vaccines remains a subject of ongoing research. This study aims to investigate the effectiveness of administering two booster doses as the third and fourth doses at different intervals to enhance vaccine protection.

Materials and methods: This study was conducted at a military regional hospital operated by the Ministry of National Defense in Taiwan. A cohort of vaccinated individuals was selected, and their vaccine potency was assessed at various time intervals following their initial vaccine administration. The study participants received booster doses as the third and fourth doses, with differing time intervals between them. The study monitored neutralizing antibody titers and other relevant parameters to assess vaccine efficacy.

Results: Our findings revealed that the potency of the SARS-CoV-2 vaccine exhibited a significant decline 80 days after the initial vaccine administration. However, a longer interval of 175 days between booster injections resulted in significantly higher neutralizing antibody titers. The individuals who received the extended interval boosters exhibited a more robust immune response, suggesting that a vaccine schedule with a 175-day interval between injections may provide superior protection against SARS-CoV-2.

Conclusion: This study underscores the importance of optimizing vaccine booster dosing schedules to maximize protection against SARS-CoV-2. The results indicate that a longer interval of 175 days between the third and fourth doses of the vaccine can significantly enhance the neutralizing antibody response, potentially offering improved protection against the virus. These findings have important implications for vaccine distribution and administration strategies in the ongoing battle against the SARS-CoV-2 pandemic. Further research and large-scale trials are needed to confirm and extend these findings for broader public health implications.

Keywords: Booster dose; COVID-19 vaccine; Neutralizing antibodies; SARS-CoV-2.