Molecular Epidemiology of Respiratory Syncytial Virus during 2019-2022 and Surviving Genotypes after the COVID-19 Pandemic in Japan.

To evaluate the changes in respiratory syncytial virus (RSV) collected between 2019 and 2022, we analyzed RSV-A and RSV-B strains from various prefectures in Japan before and after the COVID-19 pandemic. RT-PCR-positive samples collected from children with rapid test positivity at outpatient clinics in 11 prefectures in Japan were sequenced for the ectodomain of the G gene to determine the genotype. Time-aware phylogeographic analyses were performed using the second hypervariable region (HVR) of the G gene from 2012 to 2022.

Factors associated with viral RNA shedding and evaluation of potential viral infectivity at returning to school in influenza outpatients after treatment with baloxavir marboxil and neuraminidase inhibitors during 2013/2014-2019/2020 seasons in Japan: an observational study.

Background: This study assessed the differences in daily virus reduction and the residual infectivity after the recommended home stay period in Japan in patients infected with influenza and treated with baloxavir (BA), laninamivir (LA), oseltamivir (OS), and zanamivir (ZA).

Methods: We conducted an observational study on children and adults at 13 outpatient clinics in 11 prefectures in Japan during seven influenza seasons from 2013/2014 to 2019/2020. Virus samples were collected twice from influenza rapid test-positive patients at the first and second visit 4-5 days after the start of treatment.

Efficacy of edoxaban for the treatment of gynecological cancer-associated venous thromboembolism: analysis of Japanese real-world data.

Objective: Direct oral anticoagulants (DOACs) are increasingly being used for the treatment of cancer-associated venous thromboembolism (CAT). However, there is limited evidence of the efficacy of DOACs for the treatment of gynecological CAT. Thus, this study aimed to investigate the efficacy and safety of edoxaban for the treatment of gynecological CAT using Japanese real-world data.

Vaccine acquired pertussis immunity was weakened at 4 years of age and asymptomatic pertussis infection was suspected based on serological surveillance.

Serological surveillance of pertussis antibodies was performed in 118 children aged 1-12 years. The positivity of pertussis toxin (PT) antibodies was low at 4-6 years and significantly higher at 8-9 years, compared with those at 6 years. Fimbriae 2 (Fim2) antibody showed similar response to the PT antibody.

Seasonal split influenza vaccine induced IgE sensitization against influenza vaccine.

Although anaphylaxis is an extremely rare vaccine-associated adverse event, it occurred in young children following administration of the 2011/12 seasonal split influenza vaccine, which contained 2-phenoxyethanol as the preservative. These children had high levels of IgE antibodies against influenza vaccine components. We herein investigated why these children were sensitized.

Humoral immune response to influenza A(H1N1)pdm2009 in patients with natural infection and in vaccine recipients in the 2009 pandemic.

The 2009 pandemic H1N1 mainly affected adolescents and children, and most of the elderly in Japan escaped clinical illness. To clarify the role of humoral immunity in the infection, the time kinetics of hemagglutination inhibition (HI), neutralization (NT), and IgG subclass antibody response directed against influenza A(H1N1)pdm2009 were analyzed in three consecutive specimens obtained from 51 young adults and children (group 1) who contracted pandemic influenza and from 74 pediatric clinic employees (group 2) inoculated with pandemic monovalent vaccine. In group 1 patients, 6 and 30 patients had lower HI and NT antibody in the acute phase respectively.

Serum levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in human herpesvirus-6-infected infants with or without febrile seizures.

Human herpesvirus-6 (HHV-6) is a cause of exanthema subitum and, sometimes, of febrile seizures. However, the pathogenesis of febrile seizures associated with HHV-6 infection remains unclear. We investigated serum matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) levels in infants with HHV-6 infection.

Effectiveness and safety of inactivated influenza vaccination in pediatric liver transplant recipients over three influenza seasons.

Annual influenza vaccination is recommended for pediatric liver transplant recipients, who are at high risk of influenza-related complications. However, effectiveness and safety of vaccination may differ among influenza seasons in this population and have not been fully evaluated. Subjects comprised 38 pediatric liver transplant recipients with or without influenza vaccination through the 2006-2007, 2007-2008 and 2008-2009 influenza seasons.

The course of fever following influenza virus infection in children treated with oseltamivir.

Although the effectiveness of oseltamivir against influenza virus infection is well known, there has been no report analyzing the detailed time course of fever following the drug treatment in children. Oseltamivir was prescribed for 4 days to every child with a positive result for rapid immunological test for influenza virus during 2002--2003, 2003--2004, and 2004--2005 epidemics. Only those who were 1-12 years of age and prescribed oseltamivir within 24 hr after the onset of fever were included in the analysis.

Quantitative detection and rapid identification of human adenoviruses.

We have established a method of quantitative detection and rapid identification of human adenoviruses (hAdVs). Using LightCycler PCR with a primer set, we were able to amplify 554 bp of the hexon gene from each of 51 prototype strains of hAdVs. The sensitivity of LightCycler PCR was 10 copies of hAdV DNA/reaction.

Natural course of fever during influenza virus infection in children.

During the 2001-2002 epidemic of influenza virus A/H1N1, A/H3N2, and B, the authors obtained detailed profiles of fever from 118 infected children. The only treatment given was acetaminophen for temperatures greater than 39.0 degrees C.

A comparative study of the incidence of aseptic meningitis in symptomatic natural mumps patients and monovalent mumps vaccine recipients in Japan.

To compare the incidence of aseptic meningitis associated with symptomatic natural mumps infection and in mumps vaccine recipients, we conducted a prospective comparative study. Consecutive samples of 1051 children with mumps were enrolled by 10 pediatricians and 21,465 vaccine recipients by 143 pediatric primary care practitioners, from January 1, 2000 to January 1, 2003. Parents used a daily diary to record symptoms during the period of illness (15 days) or 30-day period following immunization.

Efficacy of inactivated trivalent influenza vaccine in alleviating the febrile illness of culture-confirmed influenza in children in the 2000-2001 influenza season.

During the 2000/2001 influenza season in Japan, children ranging in age from 6 months to 13 years with fever exceeding 37.5 degrees C were recruited. Vaccine efficacy was evaluated by comparing the rates of pre-seasonal vaccination between groups stratified by fever severity.

Molecular epidemiology of mumps virus in Japan and proposal of two new genotypes.

We isolated 872 strains of mumps virus from naso-pharyngeal secretions in seven different districts of Japan from January 2000 to July 2001. Among them, 57 strains were geno-typed by nucleotide sequencing in part of the hemagglutinin-neuraminidase (HN) and small hydrophobic (SH) protein regions. Four different genotypes (B, G, K, and L) of mumps virus were co-circulating in Japan and the distribution of genotypes varied in geographically different districts.