Pasteur Institute of Nha Trang

Background Rabies remains a cause of mortality in many low- and middle-income countries, with the majority of human infections resulting from dog-to-human transmission. The Integrated Bite Case Management (IBCM) model is a One Health approach that aims to strengthen rabies surveillance and response by linking the management of human bite cases with investigation of the implicated animals. This study aimed to evaluate the effectiveness of implementing IBCM in Quang Nam Province under existing resource conditions. Methodology/Principal Findings A pre–post intervention study without a control group was conducted across the entire province. During the intervention period, 11,673 animal-bite cases were recorded; IBCM identified 75 animals suspected of having rabies, of which 40 tested positive for rabies virus by RT-PCR. Most of these animals were unvaccinated, free-roaming dogs. In communes where outbreaks were detected, the average number of registered dogs increased from 507 to 543 per commune, and vaccination coverage increased from 44.1% to 72.6% within 21 days. The average number of Post-exposure prophylaxis (PEP) courses administered per month increased from 349 to 971, the proportion of high-risk exposures increased from 9.3% to 11.9%, and the proportion of delayed PEP (≥10 days after exposure) rose slightly from 5.9% to 6.6%. At the same time, the proportion of staff with good knowledge of rabies diagnosis in animals increased substantially, from 9.1% to 55.6%. The main limitations included the pre–post design and loss to follow-up of some animals, which prevented laboratory testing. Conclusion The implementation of IBCM within the existing health and veterinary systems substantially strengthened rabies surveillance and response in accordance with the One Health approach. IBCM was demonstrated to be feasible, resource-appropriate, and scalable, thereby contributing to progress toward the global goal of eliminating human deaths from dog-mediated rabies by 2030. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was reviewed and approved by the VN01057/IORG 0008555, \[NIHE, Ha Noi, VietNam\] (Approval number: NIHE IRB - 19/2024) This research was conducted as part of routine rabies surveillance and control activities implemented within the existing public health and veterinary systems. The study involved secondary analysis of surveillance data on human animal-bite cases and animal rabies investigations. No experimental interventions were conducted, and no additional procedures beyond standard public health practice were introduced. All data were collected by authorized health and veterinary personnel. Individual-level human data were anonymized and de-identified prior to analysis. As the study did not involve direct interaction with human participants and used routinely collected surveillance data, the requirement for informed consent was waived by the ethics committee. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All relevant data underlying the findings of this study are included within the manuscript and its Supporting Information files

Objective This study aims to determine the prevalence, associated factors, and molecular epidemiology of HBV infection among schoolchildren and household members (HHMs) in Vietnam. Methods A cross-sectional community survey on hepatitis B virus markers among randomly selected schoolchildren was conducted in Nha Trang City, central Vietnam. Then, a follow-up case-control study was conducted as a household contact investigation among HHMs of children who tested HBsAg-positive (cases) and HHMs of grade-matched children (1:3 ratio) who tested HBsAg-negative (controls). HBV markers, risk factors associated with HBsAg-positive, molecular epidemiology of transmission, and genome mutations were investigated. Results A total of 1,210 schoolchildren enrolled, 57.9% received HepB full vaccination, 1.1% HBsAg-positive, and 20.2% anti-HBs-positive were observed. Among household contacts of HBsAg-positive children, a high prevalence of HBsAg positivity was observed (54.5%), whereas the prevalence among household contacts of HBsAg-negative children was substantially lower (2.5%), indicating marked intra-household clustering of HBV infection. HBV-positive schoolchildren and their mothers were predominantly grouped within the same genetic clusters. Genotypes B4 (68.0%) and C1 (32.0%) were detected. No HBV drug resistance mutations were found, but vaccine-escape mutants (VEMs) and occult HBV infection (OBI)-associated mutations in preS/S, as well as other mutations, were observed. Conclusions Schoolchildren had a low HBV-positive rate, and HHMs of HBsAg-positive schoolchildren had a higher rate of HBV infection. Mutations previously associated in the literature with advanced liver disease were identified.

IntroductionDespite extensive research on SARS-CoV-2 immunity, longitudinal studies integrating functional neutralization, antigenic relationships, and host genetic variability remain limited, particularly in Southeast Asian populations with distinct HLA backgrounds. Here, we performed a longitudinal analysis of a Vietnamese COVID-19 cohort before and after vaccination to characterize determinants of cross-variant antibody responses. Our findings indicate that while HLA polymorphisms contribute to inter-individual variability following natural infection, vaccination substantially enhanced cross-variant neutralization and reduced the apparent contribution of HLA-associated variability of neutralizing responses across genetically diverse individuals.MethodsWe analyzed 189 Vietnamese COVID-19 convalescent individuals at approximately 7 months post-infection (unvaccinated) and 72 individuals at approximately 15 months (predominantly vaccinated). Anti-S1 and anti-RBD IgG were quantified by ELISA, and neutralizing antibody titers (PRNT50) were measured against Wuhan and major variants of concern. High-resolution HLA genotyping was performed using next-generation sequencing, and associations with antibody responses were evaluated using linear regression models with correction for multiple comparisons.ResultsVaccination markedly increased antibody levels and neutralizing titers across all variants, with fold-increases ranging from approximately 10-fold (Omicron) to 132-fold (Wuhan). Neutralization breadth expanded substantially after vaccination, although reduced activity against Omicron persisted. Strong correlations between binding and neutralizing antibodies were observed, particularly post-vaccination. While several HLA alleles were associated with variation in neutralizing antibody magnitude at earlier time points, multivariable analyses demonstrated that vaccination was the strongest factor associated with neutralization breadth at 15 months.ConclusionVaccination robustly enhances both the magnitude and breadth of humoral immunity in previously infected individuals, consistent with hybrid immunity. Although HLA polymorphisms contribute to inter-individual variability, their contribution appeared smaller than the effect associated with vaccination. These findings highlight how vaccination reshapes immune variability across genetically diverse populations and provide population-specific insight into long-term SARS-CoV-2 immunity.

Staphylococcus aureus (S. aureus), especially Methicillin-resistant Staphylococcus aureus (MRSA), remains a major public health concern both in hospital and community settings. The MRSA carriage situation among schoolchildren in Vietnam is limited. A cross-sectional study was conducted in March 2023 to assess the prevalence, antimicrobial resistance patterns, and molecular characteristics of MRSA among schoolchildren in Nha Trang, Vietnam. Schoolchildren from grades 1 to 12 (ages 6-18 yrs) were enrolled. Background epidemiological data and nasal swabs were collected. Nasal samples were processed at the Pasteur Institute in Nha Trang, Vietnam, for S. aureus culture. Out of 1210 participants enrolled, S. aureus prevalence was 18.3% (222/1210), of which 41% (91/222) were MRSA. Primary school children showed the highest prevalence of MRSA colonization (48%), 32.8% in secondary, and 27.8% in high school. Among MRSA isolates, high levels of resistance were detected against trimethoprim-sulfamethoxazole (100%), erythromycin (68.2%) and clindamycin (45.1%). Multidrug resistance (MDR) occurred in 30% (27/90) of MRSA isolates. Staphylococcal cassette chromosome mec (SCCmec) subtype IVa was dominant (66.0%), followed by type IV (7.0%) and type V (6.0%). MLST data revealed genetic diversity whereby ST45 dominated, followed by ST546 and ST188. Continuous MRSA surveillance is essential to monitor emerging strains in the communities.