Understanding SARS-CoV-2 Variants and Safety Countermeasures for the Fight against Omicron

Purpose: This study examines the mutation profiles and global prevalence of SARS-Cov-2 variants. We further investigate the viral characteristics of the Delta and Omicron variants, such as epidemiology and transmissibility, disease severity, immune escape and vaccine effectiveness. Moreover, safety countermeasures for the fight against the Omicron variant are explored regarding the new pandemic response strategies focused on medical response and COVID-19 guidelines for quarantine rules. Method: This study was conducted on Web-based searches about the latest updates COVID-19 from the World Health Organization, Korea Centers for Disease Control and Prevention, and the Ministry of Food and Drug Safety. In addition, we searched for the ‘SARS-CoV-2 variant”, and “COVID-19 and Delta, or Omicron” in PubMed and then reviewed the selected articles regarding variants of concern, the Delta and Omicron variants. Results: To date, there are five variants of concern available on the WHO tracking SARS-CoV-2 variants website. The Delta and Omicron variants are of particular concern among variants, and the Omicron variant is rapidly out-pacing the Delta variant worldwide to become the dominant circulating variant with a substantial growth ad-vantage having a shorter doubling time. Even though the Omicron variant has shown moderate and lower disease severity than the Delta variant, there is concern about the high possibility of immune evasion, and it is predicted to be the most prevalent variant in the Republic of Korea near future. Therefore, safety countermeasures to contain the spread of the Omicron variant will be implemented for gradual recovery to a new normal life. Conclusion: Accordingly, along with the domestic efforts such as encouraging third booster vaccination and maintaining high-level quarantine systems, international collaboration, clear and transparent communications, and even achievement of 70% coverage with COVID-19 vaccines in all countries will be necessary to battle against the SARS-CoV-2 variants and to stop the continuous prevalence of Omicron worldwide.