Effectiveness of SARS‐CoV‐2 vaccines used in Malaysia: A systematic review and meta‐analysis

Abstract Introduction: COVID-19 caused by SARS-CoV2 was declared a pandemic by WHO in March 2020 following which many vaccines were synthesised which effectively reduced the case fatality ratio. Malaysia implemented community -wide COVID-19 vaccination using ChAdOx1(AZD1222, Astra Zeneca), BNT162b2 mRNA (Pfizer BioNTech) and CoronaVac (Sinovac) vaccines in 2021. Efficacy was established by randomized control trials prior to its roll out, but the effectiveness of these vaccines in a real-world community setting can be assessed from hospital data and research articles published from 2021 onwards. Aim: This study aimed to do a systematic analysis of the available articles from various countries which used the three vaccines introduced in Malaysia and compare with the outcome in Malaysia. Methods: We performed a systematic analysis on various studies about the three vaccines from different parts of the world ,based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA) recommendations with well-defined inclusion and exclusion criteria. The studies for each vaccine were analysed for the relative risk reduction (RRR) and vaccine effectiveness. Further, a comparison between the three vaccines was attempted and compared with the effectiveness of the three vaccines in Malaysia. Results: BNT162b2 had an RRR ≥ 90% against severe symptomatic SARS-CoV-2 with very high effectiveness upon completion of two doses.ChAdOx1 vaccine effectiveness showed a wide range from 67.5% to 95.6 %. Effectiveness for CoronaVac ranged from 54- 99.9%. Meta-analysis of the data was done using Microsoft Excel. A comparison between the three vaccines showed a higher effectiveness for BNT162b2 ( 94.9%) followed by ChAdOx1 (84.7 %) and SinoVac ( 72.4%).The effectiveness of ChAdOx1 vaccine reported from our country is the highest among the studies. Conclusion: Real-world evidence shows that COVID-19 vaccines are highly effective against severe disease, hospitalization, and death. Our study validates the importance of assessing effectiveness of COVID vaccines in preventing severe COVID.