Tian Zhao

CanSino Biologics Inc., Tianjin, 300462, Tianjin, China
Author    Correspondence author
Journal of Vaccine Research, 2024, Vol. 14, No. 5   
Received: 25 Jul., 2024    Accepted: 10 Sep., 2024    Published: 20 Sep., 2024

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The emergence of various SARS-CoV-2 variants has posed significant challenges to the efficacy of COVID-19 vaccines. This stdy assesses the protection levels offered by different COVID-19 vaccines against multiple SARS-CoV-2 variants, including Alpha (B.1.1.7), Beta (B.1.351), Gamma, and Delta (B.1.617.2). The ChAdOx1 nCoV-19 (AZD1222) vaccine demonstrated reduced neutralization activity against the B.1.1.7 variant but maintained clinical efficacy. Full vaccination with mRNA vaccines showed high effectiveness against the Alpha variant and moderate effectiveness against Beta/Gamma and Delta variants, while partial vaccination was less effective. The BNT162b2 and ChAdOx1 nCoV-19 vaccines exhibited lower effectiveness after one dose against the Delta variant compared to the Alpha variant, but two doses provided substantial protection. The ChAdOx1 nCoV-19 vaccine showed limited efficacy against mild-to-moderate COVID-19 caused by the B.1.351 variant. Overall, while vaccines have significantly reduced the incidence and severity of COVID-19, the emergence of new variants necessitates ongoing evaluation of vaccine efficacy and potential updates to vaccine formulations.

COVID-19 vaccines; SARS-CoV-2 variants; Vaccine efficacy; Neutralization activity; Immunogenicity