Osong Public Health and Research Perspectives

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Replication kinetics and infectivity of SARS-CoV-2 Omicron variant sublineages recovered in the Republic of Korea: Jeong-Min Kim, Dongju Kim, Jee Eun Rhee, Cheon Kwon Yoo, Eun-Jin Kim; Osong Public Health Res Perspect. 2024;15(3):260-264. Published online June 27, 2024; DOI: https://doi.org/10.24171/j.phrp.2023.0216

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Graphical Abstract Abstract PDF Supplementary Material: Objectives
We analyzed the correlation between the infectivity and transmissibility of the severe acute respiratory syndrome coronavirus 2 Omicron sublineages BA.1, BA. 2, BA.4, and BA.5. Methods: We assessed viral replication kinetics and infectivity at the cellular level. Nasopharyngeal and oropharyngeal specimens were obtained from patients with coronavirus disease 2019, confirmed using whole-genome sequencing to be caused by the Omicron sublineages BA.1, BA.2, BA.4, or BA.5. These specimens were used to infect Vero E6 cells, derived from monkey kidneys, for the purpose of viral isolation. Viral stocks were then passaged in Vero E6 cells at a multiplicity of infection of 0.01, and culture supernatants were harvested at 12-hour intervals for 72 hours. To evaluate viral replication kinetics, we determined the cycle threshold values of the supernatants using real-time reverse transcription polymerase chain reaction and converted these values to genome copy numbers. Results: The viral load was comparable between BA.2, BA.4, and BA.5, whereas BA.1 exhibited a lower value. The peak infectious load of BA.4 was approximately 3 times lower than that of BA.2 and BA.5, while the peak load of BA.2 and BA.5 was about 7 times higher than that of BA.1. Notably, BA.1 demonstrated the lowest infectivity over the entire study period. Conclusion: Our results suggest that the global BA.5 wave may have been amplified by the higher viral replication and infectivity of BA.5 compared to other Omicron sublineages. These analyses could support the rapid assessment of the impact of novel variants on case incidence.

Original Article

Increased viral load in patients infected with severe acute respiratory syndrome coronavirus 2 Omicron variant in the Republic of Korea: Jeong-Min Kim, Dongju Kim, Nam-Joo Lee, Sang Hee Woo, Jaehee Lee, Hyeokjin Lee, Ae Kyung Park, Jeong-Ah Kim, Chae Young Lee, Il-Hwan Kim, Cheon Kwon Yoo, Eun-Jin Kim; Osong Public Health Res Perspect. 2023;14(4):272-278. Published online July 27, 2023; DOI: https://doi.org/10.24171/j.phrp.2023.0024

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2 Web of Science
2 Crossref

Graphical Abstract Abstract PDF

Objectives
Coronavirus disease 2019 (COVID-19) has been declared a global pandemic owing to the rapid spread of the causative agent, severe acute respiratory syndrome coronavirus 2. Its Delta and Omicron variants are more transmissible and pathogenic than other variants. Some debates have emerged on the mechanism of variants of concern. In the COVID-19 wave that began in December 2021, the Omicron variant, first reported in South Africa, became identifiable in most cases globally. The aim of this study was to provide data to inform effective responses to the transmission of the Omicron variant.
Methods
The Delta variant and the spike protein D614G mutant were compared with the Omicron variant. Viral loads from 5 days after symptom onset were compared using epidemiological data collected at the time of diagnosis.
Results
The Omicron variant exhibited a higher viral load than other variants, resulting in greater transmissibility within 5 days of symptom onset.
Conclusion
Future research should focus on vaccine efficacy against the Omicron variant and compare trends in disease severity associated with its high viral load.

Citations

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Replication kinetics and infectivity of SARS-CoV-2 Omicron variant sublineages recovered in the Republic of Korea
Jeong-Min Kim, Dongju Kim, Jee Eun Rhee, Cheon Kwon Yoo, Eun-Jin Kim
Osong Public Health and Research Perspectives.2024; 15(3): 260. CrossRef
Diagnostic Accuracy of the Abbott BinaxNOW COVID‐19 Antigen Card Test, Puerto Rico
Zachary J. Madewell, Chelsea G. Major, Nathan Graff, Cameron Adams, Dania M. Rodriguez, Tatiana Morales, Nicole A. Medina Lopes, Rafael Tosado, Liliana Sánchez‐González, Janice Perez‐Padilla, Hannah R. Volkman, Jorge Bertrán‐Pasarell, Diego Sainz de la Pe
Influenza and Other Respiratory Viruses.2024;[Epub] CrossRef

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