Serial Intervals and Household Transmission of SARS-CoV-2 Omicron Variant, South Korea, 2021.

To clarify transmissibility of the severe acute respiratory syndrome coronavirus 2 Omicron variant, we determined serial intervals and secondary attack rates among household contacts in South Korea. Mean serial interval for 12 transmission pairs was 2.9 days, and secondary attack rate among 25 households was 50.0%, raising concern about a rapid surge in cases.

Risk factors for SARS-CoV-2 transmission during a movie theater outbreak in Incheon in the Republic of Korea, November 2021: a retrospective study.

BACKGROUND: We examined factors contributing to the transmission of an acute respiratory virus within multi-use facilities, focusing on an outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a movie theater in the Republic of Korea. METHODS: This retrospective cohort study involved a descriptive analysis of 48 confirmed cases. Logistic regression was applied to a cohort of 80 theater attendees to identify risk factors for infection. The infection source and transmission route were determined through gene sequencing data analysis. RESULTS: Of the 48 confirmed cases, 35 were theater attendees (72.9%), 10 were family members of attendees (20.8%), 2 were friends (4.2%), and 1 was an employee (2.1%). Among the 80 individuals who attended the 3rd to 5th screenings of the day, 35 became infected, representing a 43.8% attack rate. Specifically, 28 of the 33 third-screening attendees developed confirmed SARSCoV-2, constituting an 84.8% attack rate. Furthermore, 11 of the 12 cases epidemiologically linked to the theater outbreak were clustered monophyletically within the AY.69 lineage. At the time of the screening, 35 individuals (72.9%) had received 2 vaccine doses. However, vaccination status did not significantly influence infection risk. Multivariate analysis revealed that close contacts had a 15.9-fold higher risk of infection (95% confidence interval, 4.37-78.39) than casual contacts. CONCLUSION: SARS-CoV-2 transmission occurred within the theater, and extended into the community, via a moviegoer who attended the 3rd screening during the viral incubation period after contracting the virus from a family member. This study emphasizes the importance of adequate ventilation in theaters.

Aberrant expression of let-7a miRNA in the blood of non-small cell lung cancer patients.

Abnormal expression of let-7a microRNA (miRNA) in non-small cell lung cancer (NSCLC) cells and tissue has been previously reported. Our objective was to investigate whether let-7a miRNA is aberrantly expressed in the blood of NSCLC patients. Using real-time PCR (RT-PCR), we analyzed let-7a miRNA in archived whole blood from 65 participants, 35 of whom had NSCLC and 30 of whom did not. Using RT-PCR, we also investigated the expression of let-7a miRNA in NSCLC cell lines (A549 and HCC 1588), a normal human lung fibroblast cell line (WI-38) and in 40 human NSCLC tissues. The 2(-ddCt) of let-7a miRNA in the blood of normal subjects and those with NSCLC was 3242.49±355.28 and 747.85±177.74, respectively. The relative expression of let-7a miRNA in the A549 and HCC 1588 cancer cell lines was approximately 0.3 and 0.35, respectively, compared to WI-38 cells. The 2(-ddCt) of let-7a miRNA in the normal human lung tissues and human NSCLC tissues was 42.30±3.98 and 27.73±3.86, respectively. Let-7a miRNAs were under-expressed in the blood of NSCLC patients, as well as NSCLC cells and NSCLC tissues, compared to normal controls. The possibility of using let-7a miRNA as a serologic marker for lung cancer warrants further study.