Clusters of Coronavirus Disease in Communities, Japan, January-April 2020

We analyzed 3, 184 cases of coronavirus disease in Japan and identified 61 case-clusters in healthcare and other care facilities, restaurants and bars, workplaces, and music events. We also identified 22 probable primary case-patients for the clusters; most were 20-39 years of age and presymptomatic or asymptomatic at virus transmission

The RNA Binding Protein Mex-3B Is Required for IL-33 Induction in the Development of Allergic Airway Inflammation

Allergic airway inflammation is one of the primary features of allergic asthma. Interleukin-33 (IL-33) is recognized as a key pro-inflammatory cytokine that mediates allergic airway inflammation, and its expression is elevated in this condition, but little is known about the regulatory mechanisms underlying IL-33 induction. Here, we show that the RNA binding protein Mex-3B plays a critical role in the induction of IL-33 in the development of allergic airway inflammation. We generated Mex3b−/− mice and found that they develop significantly less airway inflammation than wild-type mice due to reduced induction of IL-33. Furthermore, we show that Mex-3B directly upregulates IL-33 expression by inhibiting miR-487b-3p-mediated repression of IL-33. Moreover, we show that inhalation of an antisense oligonucleotide targeting Mex-3B suppresses allergic airway inflammation. Our data identify a signaling pathway that post-transcriptionally regulates IL-33 expression and suggest that Mex-3B could be a promising molecular target for the treatment of allergic asthma

Time-varying overdispersion of SARS-CoV-2 transmission during the periods when different variants of concern were circulating in Japan

Abstract Japan has implemented a cluster-based approach for coronavirus disease 2019 (COVID-19) from the pandemic’s beginning based on the transmission heterogeneity (overdispersion) of severe acute respiratory coronavirus 2 (SARS-CoV-2). However, studies analyzing overdispersion of transmission among new variants of concerns (VOCs), especially for Omicron, were limited. Thus, we aimed to clarify how the transmission heterogeneity has changed with the emergence of VOCs (Alpha, Delta, and Omicron) using detailed contact tracing data in Yamagata Prefecture, Japan. We estimated the time-varying dispersion parameter ( $${k}_{t}$$ k t ) by fitting a negative binomial distribution for each transmission generation. Our results showed that even after the emergence of VOCs, there was transmission heterogeneity of SARS-CoV-2, with changes in $${k}_{t}$$ k t during each wave. Continuous monitoring of transmission dynamics is vital for implementing appropriate measures. However, a feasible and sustainable epidemiological analysis system should be established to make this possible