Effectiveness of currently authorized vaccines against SARS-CoV-2 variants of concern and the future of COVID-19 vaccines

Abstract

Knowledge is still limited on the effectiveness of currently authorized COVID-19 vaccines against the numerous variants of SARS-CoV-2. Authorized vaccines are still showing high levels of effectiveness in preventing severe disease symptoms of COVID-19. However, there are several limitations to the highly effective mRNA vaccines, and the existing vaccine supply is still falling short of the global demand. Furthermore, the rapidly spreading Omicron variant has clustered mutations at the ACE2 receptor binding sites as well as at antibody sites, which happen to be the targets of widely used COVID-19 vaccines. The effectiveness of authorized vaccines on emergent variants continues to be an important point of clinical research, as well as the need to find other vaccine technology that could provide more comprehensive protection against emerging variants. This article will address current knowledge on the effectiveness of authorized vaccines and discuss other vaccine technology that could become important prevention tools in the near future against circulating SARS-CoV-2 variants of concern. This article will outline studies that suggest that vaccines focusing more on stimulating T cell response and on conserved peptides could become important in providing immunity against emergent variants of concern. Nanocarriers also continue to be an immensely promising area of vaccine development. Among nanocarrier vaccine technology, subunit adjuvant vaccines are especially gaining traction. This article will also introduce recent research that suggests that adjuvant vaccines could become important second and third generation COVID-19 vaccines. As the pandemic progresses, many considerations must be made including vaccine affordability, distribution and access. From a Canadian perspective, it will become increasingly important to put vaccine development and biomanufacturing technology in place within Canada rather than relying heavily on biotechnology companies outside of the country.