Age-specific prevalence of IgG against measles/rubella and the impact of routine and supplementary immunization activities - a multistage random cluster sampling study with mathematical modelling.

BACKGROUND: Vietnam continues to have measles and rubella outbreaks following supplementary immunization activities (SIA) and routine immunization despite both having high reported coverage. To evaluate immunization activities, age-specific immunity against measles and rubella, and the number of averted Congenital Rubella Syndrome (CRS) cases, must be estimated. METHODS: Dried blood spots were collected from 2,091 randomly selected individuals aged 1-39 years. Measles and rubella virus-specific immunoglobulin G (IgG) were measured by enzyme immunoassay. Results were considered positive at ≥120 mIU/mL for measles and ≥10 IU/mL for rubella. The number of CRS cases averted by immunization since 2014 were estimated using mathematical modelling. RESULTS: OVERALL IGG SEROPREVALENCE WAS 99.7% (95%CI: 99.2-99.9) FOR MEASLES AND 83.6% (95%CI: : 79.3-87.1) for rubella. Rubella IgG seroprevalence was higher among age groups targeted in the SIA than in non-targeted young adults (95.4% [95%CI: 92.9-97.0] vs. 72.4% [95%CI: 63.1-80.1]; P < 0.001). The estimated number of CRS cases averted in 2019 by immunization activities since 2014 ranged from 126 (95%CI: 0-460) to 883 (95%CI: 0-2271) depending on the assumed post-vaccination reduction in the force of infection. CONCLUSIONS: The results suggest the SIA was effective, while young adults born before 1998 who remain unprotected for rubella require further vaccination.

Laparoscopic median arcuate ligament section for median arcuate ligament compression syndrome initially detected as splenic infarction: a case report.

BACKGROUND: Median arcuate ligament compression syndrome (MALS) causes upper abdominal pain and at times hemodynamic abnormalities in the pancreaticoduodenal region. Herein, we present a case of a 70 year-old man, initially diagnosed with splenic infarction and was successfully treated laparoscopically. CASE PRESENTATION: A 70-year-old man with abdominal pain admitted to our hospital. Abdominal-enhanced computed tomography revealed a poorly contrasted area in the spleen and stenosis at the root of the celiac artery. Arterial dilatation was observed around the pancreaticoduodenal arcade, however, no obvious aneurysm formation or arterial dissection was observed. Abdominal-enhanced magnetic resonance imaging indicated the disappearance of the flow void at the root of the celiac artery. The patient had no history of atrial fibrillation and was diagnosed with splenic infarction due to median arcuate ligament compression syndrome. We performed a laparoscopic median arcuate ligament section with five ports. Intraoperative ultrasonography showed a retrograde blood flow in the common hepatic artery and the celiac artery. After releasing the compression, the antegrade blood flow from the celiac artery to the splenic artery, and the common hepatic artery were visualized using intraoperative ultrasonography. The postoperative course of the patient was uneventful, and he was discharged on postoperative day 9. Postoperative computed tomography a month after surgery revealed no residual stenosis of the celiac artery or dilation of the pancreaticoduodenal arcade. Furthermore, the poorly contrasted area of the spleen improved. CONCLUSIONS: Reports indicate that hemodynamic changes in the abdominal visceral arteries due to median arcuate ligament compression are related to the formation of pancreaticoduodenal aneurysms. In this case, median arcuate ligament compression syndrome caused splenic infarction by reducing blood flow to the splenic artery.

Cleavage-Activation of Respiratory Viruses - Half a Century of History from Sendai Virus to SARS-CoV-2.

Many viruses require the cleavage-activation of membrane fusion proteins by host proteases in the course of infection. This knowledge is based on historical studies of Sendai virus in the 1970s. From the 1970s to the 1990s, avian influenza virus and Newcastle disease virus were studied, showing a clear link between virulence and the cleavage-activation of viral membrane fusion proteins (hemagglutinin and fusion proteins) by host proteases. In these viruses, cleavage of viral membrane fusion proteins by furin is the basis for their high virulence. Subsequently, from the 2000s to the 2010s, the importance of TMPRSS2 in activating the membrane fusion proteins of various respiratory viruses, including seasonal influenza viruses, was demonstrated. In late 2019, severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) emerged and caused a pandemic. The virus continues to mutate, producing variants that have caused global pandemics. The spike protein of SARS-CoV-2 is characterized by two cleavage sites, each of which is cleaved by furin and TMPRSS2 to achieve membrane fusion. SARS-CoV-2 variants exhibit altered sensitivity to these proteases. Thus, studying the cleavage-activation of membrane fusion proteins by host proteases is critical for understanding the ongoing pandemic and developing countermeasures against it.

Tenascin C in pancreatic cancer-associated fibroblasts enhances epithelial mesenchymal transition and is associated with resistance to immune checkpoint inhibitor.

Tenascin C (TNC) is an extracellular matrix glycoprotein that is highly expressed in cancer stroma and is associated with tumor progression in pancreatic adenocarcinoma (PAAD). In this study, we aimed to investigate the potential involvement of TNC in the response to immune checkpoint inhibitors (ICI) among PAAD patients. Transcriptomic profiles were obtained from public databases and analyzed to compare TNC mRNA levels between tumor and normal tissues. Bioinformatic programs were used to predict paracrine communications between cancer cells and cancer-associated fibroblasts (CAFs), and the Tumor Immune Dysfunction and Exclusion (TIDE) score was calculated to predict response to ICI treatment in PAAD patients. An independent immunotherapeutic cohort was used to validate the clinical impact of the signatures. Results showed that TNC mRNA levels were significantly upregulated in tumors compared to normal tissues in PAAD, and patients with high TNC expression had significantly shorter overall survival than those with low TNC expression (P = 0.0125). TNC was predominantly expressed in CAFs of PAAD patients and was found to potentially enhance the epithelial-mesenchymal transition (EMT) of cancer cells via integrin receptors, contributing to resistance to ICI treatment. Patients with high TNC expression and high ITGαV or ITGB3 expression were associated with poor response to ICI therapy. In conclusion, these findings suggest that TNC-high CAFs play a crucial role in tumor progression and resistance to ICI therapy in PAAD patients, and targeting TNC and its interactions with cancer cells may provide a potential strategy for improving the efficacy of ICI therapy in PAAD.

The cholinesterase and C-reactive protein score is a potential predictor of pseudoaneurysm formation after pancreaticoduodenectomy in patients with soft pancreas.

BACKGROUND: Pseudoaneurysm (PA) rupture after pancreaticoduodenectomy (PD) is a life-threatening complication. Most PA cases originate from postoperative pancreatic fistulas (POPFs). Although several risk factors for POPF have been identified, specific risk factors for PA formation remain unclear. Therefore, we retrospectively analyzed PD cases with soft pancreas and proposed a novel strategy for early detection of PA formation. METHODS: Overall, 120 patients underwent PD between 2010 and 2020 at our institution; of these, 65 patients with soft pancreas were enrolled. We evaluated the clinicopathological factors influencing PA formation and developed a risk score to predict PA formation. RESULTS: In total, 11 of the 65 patients developed PAs (PA formation group: PAG), and 8 of these 11 PAs ruptured. The median time to PA formation was 15 days, with a minimum of 5 days. The PAG was significantly older than the non-PA formation group, were predominantly men, and had comorbid diabetes mellitus. Pre- and intra-operative findings were similar between the two groups. Importantly, no significant differences were found in postoperative drain amylase levels and total drain amylase content. Cholinesterase and C-reactive protein (CRP) levels on postoperative day (POD) 3 were significantly different between the two groups. Multivariate analysis showed that cholinesterase ≤ 112 U/L and CRP ≥ 16.0 mg/dl on POD 3 were independent predictors of PA formation. CONCLUSIONS: Decreased cholinesterase and elevated CRP on POD 3 (Cho-C score) are useful predictors of PA formation in cases with soft pancreas. In such cases, periodic computed tomography evaluations and strict drain management are necessary to prevent life-threatening hemorrhage.

Establishment of reference reagents for single-radial-immunodiffusion assay on the 2022/23 seasonal influenza vaccine in Japan and their quality validation.

Potency test of influenza vaccine is currently performed using a single-radial-immunodiffusion (SRID) assay, which requires a reference antigen and anti-hemagglutinin (HA) serum as reference reagents. The reagents must be newly prepared each time the strain used for vaccine production is changed. Establishing reference reagents with consistent quality is, therefore, crucial to accurately and precisely conduct vaccine potency tests. Here, we established the reference reagents for the SRID assay to conduct lot release tests of quadrivalent influenza vaccines in Japan for the 2022/23 influenza season. The potency stability during storage of some reference antigens was confirmed. Furthermore, we evaluated the cross-reactivity of each antiserum raised against the HA protein of two lineages of influenza B virus toward the different lineage of influenza B virus antigen to select a suitable procedure of SRID assay for accurate measurement. Finally, the intra-laboratory reproducibility of the SRID assay using the established reference reagents was validated, and then the SRID reagents had sufficiently consistent quality comparable to that of the reagents used for testing vaccines in past influenza seasons. Our study could contribute to the quality control of influenza vaccines.

Prediction of postoperative complications after hepatectomy with dynamic monitoring of central venous oxygen saturation.

BACKGROUND: The usefulness of static monitoring using central venous pressure has been reported for anesthetic management in hepatectomy. It is unclear whether intra-hepatectomy dynamic monitoring can predict the postoperative course. We aimed to investigate the association between intraoperative dynamic monitoring and post-hepatectomy complications. Furthermore, we propose a novel anesthetic management strategy to reduce postoperative complication. METHODS: From 2018 to 2021, 93 patients underwent hepatectomy at our hospital. Fifty-three patients who underwent dynamic monitoring during hepatectomy were enrolled. Flo Trac system was used for dynamic monitoring. The baseline central venous oxygen saturation (ScvO2) was defined as the average ScvO2 for 30 min after anesthesia induction. ScvO2 fluctuation (ΔScvO2) was defined as the difference between the baseline and minimum ScvO2. Postoperative complications were evaluated using the comprehensive complication index (CCI). RESULTS: Patients with ΔScvO2 ≥ 10% had significantly higher CCI scores (0 vs. 20.9: p = 0.043). In univariate analysis, patients with higher CCI scores demonstrated significantly higher preoperative C-reactive protein-to-lymphocyte ratio (7.51 vs. 24.49: p = 0.039), intraoperative bleeding (105 vs. 581 ml: p = 0.008), number of patients with major hepatectomy (4/45 vs. 3/8: p = 0.028), and number of patients with ΔScvO2 ≥ 10% (11/45 vs. 6/8; p = 0.010). Multivariate logistic regression analysis revealed that ΔScvO2 ≥ 10% (odds ratio: 9.53, p = 0.016) was the only independent predictor of elevated CCI. CONCLUSIONS: Central venous oxygen saturation fluctuation during hepatectomy is a predictor of postoperative complications. Anesthetic management based on intraoperative dynamic monitoring and minimizing the change in ScvO2 is a potential strategy for decreasing the risk of post-hepatectomy complications.

Assessment of the frequency of SARS-CoV-2 Omicron variant escape from RNA-dependent RNA polymerase inhibitors and 3C-like protease inhibitors.

The emergence and spread of antiviral-resistant SARS-CoV-2 is of great concern. In this study, we evaluated the propensity of Omicron variants to escape from RNA-dependent RNA polymerase (RdRP) inhibitors and 3C-like protease (3CLpro) inhibitors. SARS-CoV-2 Delta and Omicron variants were serially passaged in vitro in the presence of RdRP inhibitors (remdesivir and molnupiravir) and 3CLpro inhibitors (nirmatrelvir and lufotrelvir) to detect SARS-CoV-2 escape mutants. After five passages with 3CLpro inhibitors, mutant viruses that escaped from 3CLpro inhibitors emerged; however, in the presence of RdRP inhibitors all variants disappeared within 2-4 passages. Our findings suggest that the frequency of SARS-CoV-2 mutant escape from RdRP inhibitors is lower than that from 3CLpro inhibitors. We also found that Delta variants were more likely to acquire amino acid substitutions associated with resistance to 3CLpro inhibitors under the selective pressure of this drug compared with Omicron variants.

Molecular Diversity of Human Respiratory Syncytial Virus before and during the COVID-19 Pandemic in Two Neighboring Japanese Cities.

Human respiratory syncytial viruses (HRSVs) are divided into subgroups A and B, which are further divided based on the nucleotide sequence of the second hypervariable region (HVR) of the attachment glycoprotein (G) gene. Understanding the molecular diversity of HRSV before and during the coronavirus disease 2019 (COVID-19) pandemic can provide insights into the effects of the pandemic on HRSV dissemination and guide vaccine development. Here, we analyzed HRSVs isolated in Fukushima Prefecture from September 2017 to December 2021. Specimens from pediatric patients were collected at two medical institutions in neighboring cities. A phylogenetic tree based on the second HVR nucleotide sequences was constructed using the Bayesian Markov chain Monte Carlo method. HRSV-A (ON1 genotype) and HRSV-B (BA9 genotype) were detected in 183 and 108 specimens, respectively. There were differences in the number of HRSV strains within clusters prevalent at the same time between the two hospitals. The genetic characteristics of HRSVs in 2021 after the COVID-19 outbreak were similar to those in 2019. HRSVs within a cluster may circulate within a region for several years, causing an epidemic cycle. Our findings add to the existing knowledge of the molecular epidemiology of HRSV in Japan. IMPORTANCE Understanding the molecular diversity of human respiratory syncytial viruses during pandemics caused by different viruses can provide insights that can guide public health decisions and vaccine development.

Molecular evolutionary analyses of the fusion protein gene in human respirovirus 1.

Few evolutionary studies of the human respiratory virus (HRV) have been conducted, but most of them have focused on HRV3. In this study, the full-length fusion (F) genes in HRV1 strains collected from various countries were subjected to time-scaled phylogenetic, genome population size, and selective pressure analyses. Antigenicity analysis was performed on the F protein. The time-scaled phylogenetic tree using the Bayesian Markov Chain Monte Carlo method estimated that the common ancestor of the HRV1 F gene diverged in 1957 and eventually formed three lineages. Phylodynamic analyses showed that the genome population size of the F gene has doubled over approximately 80 years. Phylogenetic distances between the strains were short (< 0.02). No positive selection sites were detected for the F protein, whereas many negative selection sites were identified. Almost all conformational epitopes of the F protein, except one in each monomer, did not correspond to the neutralising antibody (NT-Ab) binding sites. These results suggest that the HRV1 F gene has constantly evolved over many years, infecting humans, while the gene may be relatively conserved. Mismatches between computationally predicted epitopes and NT-Ab binding sites may be partially responsible for HRV1 reinfection and other viruses such as HRV3 and respiratory syncytial virus.

Phosphatidylcholine in bile-derived small extracellular vesicles as a novel biomarker of cholangiocarcinoma.

BACKGROUND: Owing to the lack of definite diagnostic modalities, it is challenging to distinguish malignant cases of cholangiocarcinoma (CCA), which often causes biliary tract obstruction, from benign ones. Here, we investigated a novel lipid biomarker of CCA in bile-derived small extracellular vesicles (sEVs) and developed a simple detection method for clinical application. METHODS: Bile samples from seven patients with malignant diseases (hilar CCA = 4, distal CCA = 3) and eight patients with benign diseases (gallstones = 6, primary sclerosing cholangitis = 1, autoimmune pancreatitis = 1) were collected through a nasal biliary drainage tube. sEVs were isolated via serial ultracentrifugation and characterized using nanoparticle tracking analysis, transmission electron microscopy, and immunoblotting (with CD9, CD63, CD81, and TSG101). Comprehensive lipidomic analysis was performed using liquid chromatography-tandem mass spectrometry. Using a measurement kit, we further confirmed whether lipid concentrations could be used as a potential CCA marker. RESULTS: Lipidomic analysis of bile sEVs in the two groups identified 209 significantly increased lipid species in the malignant group. When focusing on lipid class, phosphatidylcholine (PC) level was 4.98-fold higher in the malignant group than in the benign group (P = 0.037). The receiver operating characteristic (ROC) curve showed a sensitivity of 71.4%, a specificity of 100%, and an area under the curve (AUC) of 0.857 (95% confidence interval [CI]:0.643-1.000). Using a PC assay kit, the ROC curve showed a cutoff value of 16.1 µg/mL, a sensitivity of 71.4%, a specificity of 100%, and an AUC of 0.839 (95% CI: 0.620-1.000). CONCLUSION: PC level in sEVs from human bile is a potential diagnostic marker for CCA and can be assessed by a commercially available assay kit.

Comparison of population-based measles-rubella immunoglobulin G antibody prevalence between 2014 and 2019 in Lao People's Democratic Republic: Impacts of the national immunization program.

OBJECTIVES: We evaluated the effectiveness of the Lao People's Democratic Republic's measles-rubella immunization program using the seroprevalence from two cross-sectional surveys. METHODS: The nationwide surveys occurred in 2014 and 2019 using a multistage cluster sampling, both requiring samples from 2184 individuals from 52 randomly selected villages. Immunoglobulin G titers, measured using enzyme-linked immunosorbent assay, were considered positive at ≥120 mIU/ml (measles) and ≥10 IU/ml (rubella). We calculated the vaccination-related reduction in the force of rubella infection and the number of congenital rubella syndrome cases averted in 2019. RESULTS: We collected 2135 (women: 55.2%, mean age: 23.2 years) and 2001 (52.7%, 23.1 years) samples in 2014 and 2019, respectively. During 2014-2019, immunoglobulin G prevalence increased from 83.9% (95% confidence interval [CI]: 83.8-84.0) to 98.3% (97.7-98.8) for measles and from 75.4% (75.3-75.5) to 87.8% (86.4-89.2) for rubella. The most plausible reduction in the average force of rubella infection was 100% (95% CI: 28-100) since vaccination started, averting 78 (95% CI: 42-128) congenital rubella syndrome cases in 2019. CONCLUSION: This is the first population-based study for measles and rubella at two different time points in developing countries. Measles and rubella seroprevalence increased significantly during 2014-2019, greatly exceeding the immunity thresholds for their elimination.

Generation of a photocontrollable recombinant bovine parainfluenza virus type 3.

Bovine parainfluenza virus type 3 (BPIV3) is a promising vaccine vector against various respiratory virus infections, including the human PIV3, respiratory syncytial virus, and severe acute respiratory syndrome-coronavirus 2 infections. In this study, we combined the Magnet system and reverse genetic approach to generate photocontrollable BPIV3. An optically controllable Magnet gene was inserted into the H2 region of the BPIV3 large protein gene, which encodes an RNA-dependent RNA polymerase. The generated photocontrollable BPIV3 grew in specific regions of the cell sheet only when illuminated with blue light, suggesting that spatiotemporal control can aid in safe clinical applications of BPIV3.

The anti-influenza virus drug favipiravir has little effect on replication of SARS-CoV-2 in cultured cells.

Favipiravir (T-705, commercial name Avigan), a drug developed to treat influenza virus infection, has been used in some countries as an oral treatment for COVID-19; however, its clinical efficacy in this context is controversial.….

Demonstration of bacterium-free very rapid reverse genetics system using mumps virus.

The reverse genetics system is a very powerful tool for analyzing the molecular mechanisms of viral propagation and pathogenesis. However, full-length genome plasmid construction is highly time-consuming and laborious, and undesired mutations may be introduced by Escherichia coli. This study shows a very rapid E. coli-free method of full-genome construction using the mumps virus as an example. This method was able to reduce dramatically the time for full-genome construction, which was used very efficiently for virus rescue, from several days or more to ~2 days, with a similar accuracy and yield to the conventional method using E. coli/plasmid.

Establishment of measles virus receptor-expressing Vero cells lacking functional poliovirus receptors.

Global efforts are underway to eliminate measles and rubella, and active viral surveillance is the key to achieving this goal. In addition, the World Health Organization announced guidelines for handling materials potentially infectious for poliovirus (PV) to minimize the risk of PV reintroduction and to achieve PV eradication. To support global efforts, we established new PV-non-susceptible cell lines that are useful for the isolation of measles virus (MeV) and rubella virus (RuV) (Vero ΔPVR1/2 hSLAM+). In the cell lines, MeV and RuV replicated efficiently, with no concern regarding PV replication.

Molecular epidemiology of human metapneumovirus before and after COVID-19 in East Japan in 2017-2022.

Human metapneumovirus (hMPV) is genetically classified into two major subgroups, A and B, based on attachment glycoprotein (G) gene sequences, and the A2 subgroup is further separated into three subdivisions A2a, A2b (A2b1), and A2c (A2b2). The appearance of subgroup A2c viruses carrying a 180- or 111-nucleotide duplication in the G gene (A2c180nt-dup or A2c111nt-dup) have been reported in Japan and Spain. The pandemic of coronavirus disease 2019 (COVID-19) disrupted the epidemiological kinetics of other respiratory viruses, including hMPV. In this study, we analysed the sequences of hMPV isolates obtained from 2017 to 2022 in Tokyo and Fukushima, i.e., before and after COVID-19. Subgroup A hMPVs were detected in 2017 to 2019, and most cases were A2c111nt-dup, suggesting there was continuous momentum of this clade, identical to the global situation. Subgroup B, but not subgroup A, viruses were detected in 2022, after the COVID-19 peak. Phylogenetic analysis showed that these resumed subgroup B viruses were closely related to the viruses detected in 2013 to 2016 in Yokohama and in 2019 in Fukushima, suggesting a reappearance of local endemic viruses in East Japan.

SNARE protein USE1 is involved in the glycosylation and the expression of mumps virus fusion protein and important for viral propagation.

Mumps virus (MuV) is the etiological agent of mumps, a disease characterized by painful swelling of the parotid glands and often accompanied by severe complications. To understand the molecular mechanism of MuV infection, a functional analysis of the involved host factors is required. However, little is known about the host factors involved in MuV infection, especially those involved in the late stage of infection. Here, we identified 638 host proteins that have close proximity to MuV glycoproteins, which are a major component of the viral particles, by proximity labeling and examined comprehensive protein-protein interaction networks of the host proteins. From siRNA screening and immunoprecipitation results, we found that a SNARE subfamily protein, USE1, bound specifically to the MuV fusion (F) protein and was important for MuV propagation. In addition, USE1 plays a role in complete N-linked glycosylation and expression of the MuV F protein.

Membrane Sphingomyelin in Host Cells Is Essential for Nucleocapsid Penetration into the Cytoplasm after Hemifusion during Rubella Virus Entry.

The lipid composition of the host cell membrane is one of the key determinants of the entry of enveloped viruses into cells. To elucidate the detailed mechanisms behind the cell entry of rubella virus (RuV), one of the enveloped viruses, we searched for host factors involved in such entry by using CRISPR/Cas9 genome-wide knockout screening, and we found sphingomyelin synthase 1 (SMS1), encoded by the SGMS1 gene, as a candidate. RuV growth was strictly suppressed in SGMS1-knockout cells and was completely recovered by the overexpression of enzymatically active SMS1 and partially recovered by that of SMS2, another member of the SMS family, but not by that of enzymatically inactive SMS1. An entry assay using pseudotyped vesicular stomatitis virus possessing RuV envelope proteins revealed that sphingomyelin generated by SMSs is crucial for at least RuV entry. In SGMS1-knockout cells, lipid mixing between the RuV envelope membrane and the membrane of host cells occurred, but entry of the RuV genome from the viral particles into the cytoplasm was strongly inhibited. This indicates that sphingomyelin produced by SMSs is essential for the formation of membrane pores after hemifusion occurs during RuV entry. IMPORTANCE Infection with rubella virus during pregnancy causes congenital rubella syndrome in infants. Despite its importance in public health, the detailed mechanisms of rubella virus cell entry have only recently become somewhat clearer. The E1 protein of rubella virus is classified as a class II fusion protein based on its structural similarity, but it has the unique feature that its activity is dependent on calcium ion binding in the fusion loops. In this study, we found another unique feature, as cellular sphingomyelin plays a critical role in the penetration of the nucleocapsid into the cytoplasm after hemifusion by rubella virus. This provides important insight into the entry mechanism of rubella virus. This study also presents a model of hemifusion arrest during cell entry by an intact virus, providing a useful tool for analyzing membrane fusion, a biologically important phenomenon.

Nationwide and long-term molecular epidemiologic studies of mumps viruses that circulated in Japan between 1986 and 2017.

In Japan, major mumps outbreaks still occur every 4-5 years because of low mumps vaccine coverage (30-40%) owing to the voluntary immunization program. Herein, to prepare for a regular immunization program, we aimed to reveal the nationwide and long-term molecular epidemiological trends of the mumps virus (MuV) in Japan. Additionally, we performed whole-genome sequencing (WGS) using next-generation sequencing to assess results from conventional genotyping using MuV sequences of the small-hydrophobic (SH) gene. We analyzed 1,064 SH gene sequences from mumps clinical samples and MuV isolates collected from 25 prefectures from 1986 to 2017. The results showed that six genotypes, namely B (110), F (1), G (900), H (3), J (41), and L (9) were identified, and the dominant genotypes changed every decade in Japan since the 1980s. Genotype G has been exclusively circulating since the early 2000s. Seven clades were identified for genotype G using SH sequence-based classification. To verify the results, we performed WGS on 77 representative isolates of genotype G using NGS and phylogenetically analyzed them. Five clades were identified with high bootstrap values and designated as Japanese clade (JPC)-1, -2, -3, -4, -5. JPC-1 and -3 accounted for over 80% of the total genotype G isolates (68.3 and 13.8%, respectively). Of these, JPC-2 and -5, were newly identified clades in Japan through this study. This is the first report describing the nationwide and long-term molecular epidemiology of MuV in Japan. The results provide information about Japanese domestic genotypes, which is essential for evaluating the mumps elimination progress in Japan after the forthcoming introduction of the mumps vaccine into Japan's regular immunization program. Furthermore, the study shows that WGS analysis using NGS is more accurate than results obtained from conventional SH sequence-based classification and is a powerful tool for accurate molecular epidemiology studies.