SARS-CoV-2 Omicron Variant of Concern: Everything You Wanted to Know about Omicron but Were Afraid to Ask

Dong Hoon Shin, Davey M. Smith, Jun Yong Choi

Research output: Contribution to journalReview articlepeer-review


As soon as the first case of the omicron variant of severe acute respiratory syndrome coronavirus 2 was reported in November 2021, it quickly spread worldwide with the emergence of several subvariants. Compared to previous variants, omicron was heavily mu-tated, especially for those in the Spike (S) protein and its receptor-binding domain. These mutations allowed the viruses to evade immune responses (i.e., previous infections and vaccine-elicited) and increase in transmissibility. Although vaccine effectiveness is decreased for omicron, boosters remain effective for protecting against severe diseases. Also, bivalent vaccines have been developed to increase vaccine effectiveness. Interestingly, although omicron is highly infectious, it has less morbidity and mortality compared to previously identified variants, such as delta. Additionally, the mutations that allow the virus to evade immune responses also allow it to evade many of the monoclonal antibodies developed at the beginning of the pandemic for treatment. Here, we reviewed the omicron variant’s epidemiology, genetics, transmissibility, disease severity, and responsiveness to vaccine and treatments.

Original languageEnglish
Pages (from-to)977-983
Number of pages7
JournalYonsei medical journal
Issue number11
Publication statusPublished - 2022 Nov

Bibliographical note

Funding Information:
This work was supported by the Korea National Institute of Infectious Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency (#2021-ER1902–00 and #2021-ER2601-0), the 2020 Joint Research Project of Institutes of Science and Technology (grant no. HI14C1324), National Institute of Health (AI036214), John and Mary Tu Foundation, and Pendelton Foundation.

Publisher Copyright:
© Yonsei University College of Medicine 2022.

All Science Journal Classification (ASJC) codes

  • Medicine(all)


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