Molecular and Epidemiological Analysis of Respiratory Syncytial Virus Detected in Tokyo, Japan in 2021 Season.

During the COVID-19 pandemic in 2021, Japan experienced an outbreak of respiratory syncytial virus (RSV) infection. A total of 51 RSV cases were detected from the infant specimens, including 38 rhinorrhea and 13 nasopharyngeal swabs, collected at the Tokyo Metropolitan Institute of Public Health. Of these 51 cases, 12 belonged to RSV-A and 39 to RSV-B. G protein gene sequences of RSV-A belonged to the ON1 genotype, whereas RSV-B belonged to the BA9 genotype; thus, different types of RSV were detected during the same period, suggesting that the unusual 2021 RSV season was not due to a single strain or genotype. Of all RSV-positive cases, the proportion of cases aged ≥2 years was 56.8% in 2021, which was higher than 31.2% in the past 5 years. This indicates that infants aged <1 year who were originally susceptible to RSV infection were less likely to be infected with RSV because of the COVID-19 control measures. The 2021 epidemic peaked in the 28th week, which was 9 weeks earlier than the average from 2016 to 2020. It seems necessary to accumulate and analyze further data, such as factors that became an outbreak and the characteristics of the detected viruses in 2021.

Use of a multiplex polymerase chain reaction assay for the early detection of an outbreak of human parainfluenza virus type 3 infection in a nursery school during the COVID-19 pandemic.

Introduction: Although outbreaks of parainfluenza virus type 3 (PIV-3) have been reported in children, to our knowledge none have been reported in a nursery school. As the symptoms of PIV-3 infection are similar to those of COVID-19 infection, accurate diagnosis of PIV-3 and other respiratory viruses is important during the COVID-19 pandemic. Aims: We experienced an outbreak of upper respiratory symptoms at a nursery school in Miyagi Prefecture, Japan, from 29/5/2021 to 13/6/2021 and aimed to determine the causative organism(s). Methods: A multiplex polymerase chain reaction (PCR) assay which enabled rapid detection of a variety of causative microorganisms of respiratory tract infections was used to analyse 13 nasopharyngeal swabs collected during the outbreak. Infection Prevention and control measures were implemented to prevent further spread of infection. Results: All 13 samples were positive for PIV-3 infection. 2 of the 13 samples were also positive for rhinovirus/enterovirus and 1 sample was also positive rhinovirus/enterovirus and coronavirus NL 63. No samples were positive for SARS-CoV-2. Discussion: Children in school settings are especially vulnerable to respiratory viral infections, including COVID-19. Children under two years are unable to wear masks reliably, and the COVID-19 vaccine was approved only for older children. Multiplex PCR assays can be used for the rapid diagnosis of respiratory infections. Conclusion: We identified an outbreak of PIV-3 in a nursery school during the COVID-19 pandemic. The investigation of the outbreak highlighted that it was important not to overlook other respiratory infections including PIV-3 during the COVID-19 pandemic. The multiplex PCR assay provided rapid and accurate diagnosis of the causative organisms in the outbreak and helped to direct appropriate interventions to control the outbreak.

Molecular epidemiological features of SARS-CoV-2 in Japan, 2020-1.

There were five epidemic waves of coronavirus disease 2019 in Japan between 2020 and 2021. It remains unclear how the domestic waves arose and abated. To better understand this, we analyzed the pangenomic sequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and characterized the molecular epidemiological features of the five epidemic waves in Japan. In this study, we performed deep sequencing to determine the pangenomic SARS-CoV-2 sequences of 1,286 samples collected in two cities far from each other, Tokyo Metropolis and Nagoya. Then, the spatiotemporal genetic changes of the obtained sequences were compared with the sequences available in the Global Initiative on Sharing All Influenza Data (GISAID) database. A total of 873 genotypes carrying different sets of mutations were identified in the five epidemic waves. Phylogenetic analysis demonstrated that sharp displacements of lineages and genotypes occurred between consecutive waves over the 2 years. In addition, a wide variety of genotypes were observed in the early half of each wave, whereas a few genotypes were detected across Japan during an entire wave. Phylogenetically, putative descendant genotypes observed late in each wave displayed regional clustering and evolution in Japan. The genetic diversity of SARS-CoV-2 displayed uneven dynamics during each epidemic wave in Japan. Our findings provide an important molecular epidemiological basis to aid in controlling future SARS-CoV-2 epidemics.

Isolation of human monoclonal antibodies with neutralizing activity to a broad spectrum of SARS-CoV-2 viruses including the Omicron variants.

Monoclonal antibody therapy is a promising option for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and a cocktail of antibodies (REGN-COV) has been administered to infected patients with a favorable outcome. However, it is necessary to continue generating novel sets of monoclonal antibodies with neutralizing activity because viral variants can emerge that show resistance to the currently utilized antibodies. Here, we isolated a new cocktail of antibodies, EV053273 and EV053286, from peripheral blood mononuclear cells derived from convalescent patients infected with wild-type SARS-CoV-2. EV053273 exerted potent antiviral activity against the Wuhan wild-type virus as well as the Alpha and Delta variants in vitro, whereas the antiviral activity of EV053286 was moderate, but it had a wide-range of suppressive activity on the wild-type virus as well as the Alpha, Beta, Delta, Kappa, Omicron BA.1, and BA.2 variants. With the combined use of EV053273 and EV053286, we observed similar inhibitory effects on viral replication as with REGN-COV in vitro. We further assessed their activity in vivo by using a mouse model infected with a recently established viral strain with adopted infectious activity in mice. Independent experiments revealed that the combined use of EV053273 and EV053286 or the single use of each monoclonal antibody efficiently blocked infection in vivo. Together with data showing that these two monoclonal antibodies could neutralize REGN-COV escape variants and the Omicron variant, our findings suggest that the EV053273 and EV053286 monoclonal antibody cocktail is a novel clinically applicable therapeutic candidate for SARS-CoV-2 infection.

Relative bradycardia in patients with moderate-to-severe COVID-19: a retrospective cohort study.

Coronavirus-related disease (COVID-19) can result in relative bradycardia; however, there are no reports on relative bradycardia in patients with moderate-to-severe COVID-19 who require oxygen. We retrospectively investigated 45 patients with moderate-to-severe COVID-19 and examined the relationship between heart rate and body temperature at the time of initiating oxygen or mechanical ventilation. For three consecutive days after initiating oxygen therapy, body temperature (day's highest temperature), heart rate, and other vital signs were measured simultaneously. We checked for relative bradycardia and analyzed the differences between patients with moderate COVID-19 (oxygen requirement ≤ 5 L/min) and those with severe COVID-19 (oxygen requirement ≥ 5 L/min). Of the 45 patients, 28 and 17 had moderate and severe COVID-19, respectively. The heart rate increased with increasing body temperature, and almost all patients satisfied the criteria of relative bradycardia. In Spearman's rank correlation analysis, body temperature was significantly correlated with heart rate (ρ = 0.483, p = 0.012) in moderately ill patients but not in severely ill patients (ρ = 0.261, p = 0.297). Multiple regression analysis revealed that the severity of COVID-19 and body temperature were independent predictors of heart rate. The predicted change in heart rate was 6.0 beats/min for each 1 °C rise in body temperature. Relative bradycardia was suggested to be a characteristic finding in patients with moderate-to-severe COVID-19 who require oxygen. Additionally, severely ill patients were more likely to develop relative bradycardia than moderately ill patients. Focusing on the relationship between heart rate and body temperature might help clinicians diagnose this disease in patients with worsening respiratory failure.

Granulomatosis with Polyangiitis Following Pfizer-BioNTech COVID-19 Vaccination.

We report the first case of proteinase 3 (PR3)- antineutrophil cytoplasmic antibody (ANCA)-positive granulomatosis with polyangiitis (GPA) with predominant ears, nose, and throat (ENT) manifestations following COVID-19 vaccination. A 63-year-old woman presented with aural fullness three days after vaccination. She presented with progressive rhinosinusitis and otitis media leading to profound hearing loss within three weeks. Clinical imaging revealed soft-tissue shadows in the paranasal sinuses with multiple pulmonary nodules, and histopathology was consistent with a diagnosis of GPA. It is crucial to be wary of the possibility of GPA in patients who received COVID-19 vaccines due to its rapid disease progression.