SARS-CoV-2 variants of concern

Jun Yong Choi, Davey M. Smith

Research output: Contribution to journalReview articlepeer-review

97 Citations (Scopus)


Since the COVID-19 pandemic first began in December 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has continuously evolved with many variants emerging across the world. These variants are categorized as the variant of interest (VOI), variant of concern (VOC), and variant under monitoring (VUM). As of September 15, 2021, there are four SARS-CoV-2 lineages designated as the VOC (alpha, beta, gamma, and delta variants). VOCs have increased transmissibility compared to the original virus, and have the potential for increasing disease severity. In addition, VOCs exhibit decreased susceptibility to vaccine-induced and infection-induced immune responses, and thus possess the ability to reinfect previously infected and recovered indi-viduals. Given their ability to evade immune responses, VOC are less susceptible to monoclonal antibody treatments. VOCs can also impact the effectiveness of mRNA and adenovirus vector vaccines, although the currently authorized COVID-19 vaccines are still effective in preventing infection and severe disease. Current measures to reduce transmission as well as efforts to monitor and understand the impact of variants should be continued. Here, we review the molecular features, epidemiology, impact on trans-missibility, disease severity, and vaccine effectiveness of VOCs.

Original languageEnglish
Pages (from-to)961-968
Number of pages8
JournalYonsei medical journal
Issue number11
Publication statusPublished - 2021 Nov

Bibliographical note

Funding Information:
This work was supported by a research program funded by the Korea Disease Control and Prevention Agency (2021-ER1902-0) and a grant from the Ministry of Health & Welfare, Republic of Korea (grant no. HI14C1324).

Publisher Copyright:
© Yonsei University College of Medicine 2021.

All Science Journal Classification (ASJC) codes

  • Medicine(all)


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