Comparison of the Clinical and Virological Characteristics of SARS-COV-2 Omicron BA.1/BA.2 and Omicron BA. 5 Variants: A Prospective Cohort Study

초록

Background: Data on the clinical and virological characteristics of Omicron BA.5, compared with those of Omicron BA.1/BA.2 arelimited. Methods: We prospectively enrolled healthcare workers with a confirmed diagnosis of coronavirus disease 2019 (COVID-19) at a tertiary hospital in Seoul, South Korea between January 14, 2022 and August 3, 2022. Each participant recorded theirdaily symptoms using a 5-score scale and daily saliva samples were collected. Genome sequencing, genomic and subgenomicRNA assessment, and culture-based virus isolation were performed on the saliva samples. Results: Of the 82 enrolledparticipants (BA.1/BA.2, n=40 [48%]; BA.5, n=42 [52%]), 75 (94%) received three COVID-19 vaccine doses between Novemberand December 2021. Symptoms such as fever (39% vs. 88%, P<0.001), chills (41% vs. 68%, P=0.03), myalgia (54% vs. 85%,P=0.007), and headache (46% vs. 73%, P=0.03) were more common in the BA.5 group than in the BA.1/BA.2 group, andsystemic symptom scores at the symptom onset were significantly higher in the BA.5 group than in the BA.1/BA.2 group(P=0.046). The time taken for genomic and subgenomic RNA clearance was similar between both groups (median 7 days vs. 7days, P=0.73 and median 5 days vs. 6 days, P=0.61, respectively; Figure 1). However, the viable viral shedding period wassignificantly shorter in the BA.5 group than in the BA.1/BA.2 group (median 2.5 days vs. 4 days, P<0.001; Figure 1). Conclusion:Patients infected with Omicron BA.5 variant had more severe initial systemic symptoms but exhibited shortened viable viralshedding period than those with Omicron BA.1/BA2