Suppression of the alpha, delta, and omicron variants of SARS-Cov-2 in Taiwan

Hsiao-Hui Tsou; Fang-Jing Lee; Shiow-Ing Wu; Byron Fan; Hsiao-Yu Wu; Yu-Hsuan Lin; Ya-Ting Hsu; Chieh Cheng; Yu-Chieh Cheng; Wei-Ming Jiang; Hung-Yi Chiou; Wei J Chen; Chao A Hsiung; Pau-Chung Chen; Huey-Kang Sytwu

doi:10.1371/journal.pone.0300303

Suppression of the alpha, delta, and omicron variants of SARS-Cov-2 in Taiwan

PLoS One. 2024 Mar 18;19(3):e0300303. doi: 10.1371/journal.pone.0300303. eCollection 2024.

Authors

Hsiao-Hui Tsou^{1

2}, Fang-Jing Lee¹, Shiow-Ing Wu¹, Byron Fan³, Hsiao-Yu Wu¹, Yu-Hsuan Lin^{1

4

5

6}, Ya-Ting Hsu¹, Chieh Cheng¹, Yu-Chieh Cheng¹, Wei-Ming Jiang¹, Hung-Yi Chiou^{1

7

8}, Wei J Chen^{9

10}, Chao A Hsiung¹, Pau-Chung Chen^{11

12

13

14}, Huey-Kang Sytwu¹⁵

Affiliations

¹ Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan.
² Graduate Institute of Biostatistics, College of Public Health, China Medical University, Taichung, Taiwan.
³ Brown University, Providence, Rhode Island, United States of America.
⁴ Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan.
⁵ Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan.
⁶ Institute of Health Behaviors and Community Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan.
⁷ School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan.
⁸ Master's Program in Applied Epidemiology, College of Public Health, Taipei Medical University, Taipei, Taiwan.
⁹ Center for Neuropsychiatric Research, National Health Research Institutes, Zhunan, Miaoli County, Taiwan.
¹⁰ Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
¹¹ National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan.
¹² Institute of Environmental and Occupational Health Sciences, National Taiwan University College of Public Health, Taipei, Taiwan.
¹³ Department of Public Health, National Taiwan University College of Public Health, Taipei, Taiwan.
¹⁴ Department of Environmental and Occupational Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
¹⁵ National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Miaoli County, Taiwan.

Abstract

Background: Taiwan was a coronavirus disease 2019 (COVID-19) outlier, with an extraordinarily long transmission-free record: 253 days without locally transmitted infections while the rest of the world battled wave after wave of infection. The appearance of the alpha variant in May 2021, closely followed by the delta variant, disrupted this transmission-free streak. However, despite low vaccination coverage (<1%), outbreaks were well-controlled.

Methods: This study analyzed the time to border closure and conducted one-sample t test to compare between Taiwan and Non-Taiwan countries prior to vaccine introduction. The study also collected case data to observe the dynamics of omicron transmission. Time-varying reproduction number,Rt, was calculated and was used to reflect infection impact at specified time points and model trends of future incidence.

Results: The study analyzed and compare the time to border closure in Taiwan and non-Taiwan countries. The mean times to any border closure from the first domestic case within each country were -21 and 5.98 days, respectively (P < .0001). The Taiwanese government invested in quick and effective contact tracing with a precise quarantine strategy in lieu of a strict lockdown. Residents followed recommendations based on self-discipline and unity. The self-discipline in action is evidenced in Google mobility reports. The central and local governments worked together to enact non-pharmaceutical interventions (NPIs), including universal masking, social distancing, limited unnecessary gatherings, systematic contact tracing, and enhanced quarantine measures. The people cooperated actively with pandemic-prevention regulations, including vaccination and preventive NPIs.

Conclusions: This article describes four key factors underlying Taiwan's success in controlling COVID-19 transmission: quick responses; effective control measures with new technologies and rolling knowledge updates; unity and cooperation among Taiwanese government agencies, private companies and organizations, and individual citizens; and Taiwanese self-discipline.

Copyright: © 2024 Tsou et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

MeSH terms

COVID-19* / epidemiology
COVID-19* / prevention & control
Communicable Disease Control
Humans
SARS-CoV-2* / genetics
Taiwan / epidemiology

Supplementary concepts

SARS-CoV-2 variants

Grants and funding

(1)Initials of the authors who received each award:H.H.T. (2)Grant numbers awarded to each author:grant PH-111-PP-02, PH-111-GP-02, PH-112-PP-02, and PH-112-GP-02 (3)The full name of each funder:National Health Research Institutes (4)URL of each funder website:https://www.nhri.edu.tw/ (5)Did the sponsors or funders play any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript? NO - Include this sentence at the end of your statement: The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.