Effectiveness of Booster Vaccinations on the Control of COVID-19 during the Spread of Omicron Variant in Malaysia

Matthew Tze Jian Wong; Satvinder Singh Dhaliwal; Venugopal Balakrishnan; Fazlina Nordin; Mohd Nor Norazmi; Gee Jun Tye

doi:10.3390/ijerph20021647

Effectiveness of Booster Vaccinations on the Control of COVID-19 during the Spread of Omicron Variant in Malaysia

Int J Environ Res Public Health. 2023 Jan 16;20(2):1647. doi: 10.3390/ijerph20021647.

Authors

Matthew Tze Jian Wong¹, Satvinder Singh Dhaliwal^{1

2

3

4}, Venugopal Balakrishnan¹, Fazlina Nordin⁵, Mohd Nor Norazmi^{6

7}, Gee Jun Tye¹

Affiliations

¹ Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Minden 11800, Malaysia.
² Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Perth 6102, Australia.
³ Duke-NUS Medical School, National University of Singapore, Singapore 119077, Singapore.
⁴ Office of the Provost, Singapore University of Social Sciences, Singapore 599494, Singapore.
⁵ Centre for Tissue Engineering and Regenerative Medicine (CTERM), Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia.
⁶ School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Malaysia.
⁷ Malaysian Genome and Vaccine Institute, National Institutes of Biotechnology Malaysia, Kajang 43000, Malaysia.

Abstract

(1) Background: The assessment of vaccine effectiveness against the Omicron variant is vital in the fight against COVID-19, but research on booster vaccine efficacy using nationwide data was lacking at the time of writing. This study investigates the effectiveness of booster doses on the Omicron wave in Malaysia against COVID-19 infections and deaths; (2) Methods: This study uses nationally representative data on COVID-19 from 1 January to 31 March 2022, when the Omicron variant was predominant in Malaysia. Daily new infections, deaths, ICU utilization and Rt values were compared. A screening method was used to predict the vaccine effectiveness against COVID-19 infections, whereas logistic regression was used to estimate vaccine effectiveness against COVID-19-related deaths, with efficacy comparison between AZD1222, BNT162b2 and CoronaVac; (3) Results: Malaysia's Omicron wave started at the end of January 2022, peaking on 5 March 2022. At the time of writing, statistics for daily new deaths, ICU utilization, and effective reproductive values (Rt) were showing a downtrend. Boosted vaccination is 95.4% (95% CI: 95.4, 95.4) effective in curbing COVID-19 infection, compared to non-boosted vaccination, which is 87.2% (95% CI: 87.2, 87.2). For symptomatic infection, boosted vaccination is 97.4% (95% CI: 97.4, 97.4) effective, and a non-boosted vaccination is 90.9% (95% CI: 90.9, 90.9). Against COVID-19-related death, boosted vaccination yields a vaccine effectiveness (VE) of 91.7 (95% CI: 90.6, 92.7) and full vaccination yields a VE of 65.7% (95% CI: 61.9, 69.1). Looking into the different vaccines as boosters, AZD1222 is 95.2% (CI 95%: 92.7, 96.8) effective, BNT162b2 is 91.8% (CI 95%: 90.7, 92.8) effective and CoronaVac is 88.8% (CI 95%: 84.9, 91.7) effective against COVID-19 deaths. (4) Conclusions: Boosters are effective in increasing protection against COVID-19, including the Omicron variant. Given that the VE observed was lower, CoronaVac recipients are encouraged to take boosters due to its lower VE.

Keywords: COVID-19; Malaysia; Omicron; booster; vaccine effectiveness.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

BNT162 Vaccine*
COVID-19* / epidemiology
COVID-19* / prevention & control
ChAdOx1 nCoV-19
Humans
Malaysia / epidemiology
SARS-CoV-2
Vaccination

Substances

sinovac COVID-19 vaccine
BNT162 Vaccine
ChAdOx1 nCoV-19

Supplementary concepts

SARS-CoV-2 variants

Grants and funding

This research was funded by the MINISTRY OF HIGHER EDUCATION MALAYSIA for via the Higher Institution Centre of Excellence (HICoE) grant 311/CIPPM/4401005 and SUKUK Prihatin Special Funding 203.PPSK.6790004.