Poliovirus surveillance in Mayotte, Indian Ocean, reveals encephalomyocarditis virus type 1 and a wide diversity of non-polio enteroviruses.

Efficacy of influenza vaccines and its relationship with immunological surrogate endpoints: a systematic review and meta-analysis of randomized controlled trial.

Whole-genome sequencing as a regulatory tool for quality control of Leptospira strains for vaccines and diagnostics.

Understanding the low effectiveness of influenza vaccines in older adults of South Korea: an exploration of contributing factors.

ABSTRACT Human Papillomavirus (HPV) vaccination has been implemented for more than 15 years to prevent HPV infection and associated precancerous lesions. However, limited data are available regarding the long-term impacts of HPV vaccination, particularly concerning cross-protection and type replacement. Using data from the 2007–2016 National Health and Nutrition Examination Survey (NHANES), we employed the survey-weighted Student’s t-tests, chi-square tests, and logistic regression models to examine the association between vaccine effectiveness and timing of vaccination. Among 9040 females aged 18 years and over, vaccination showed great effectiveness against both vaccine-targeted and non-vaccine-targeted high-risk HPV (hrHPV) among those vaccinated before sexual debut. After full adjustment, participants vaccinated after sex had a 48% increased risk of hrHPV infection (OR (95% CI) = 1.48 (1.16, 1.88)) compared to unvaccinated participants, and their sexual behaviors were more active as well. The most prevalent HPV subtypes were HPV 16/51/52/66, and the prevalence of subtypes 18/35/52/66/68 differed significantly across racial groups. Despite the prevalence of most hrHPV subtypes declined continuously or fluctuated over time, it is noteworthy that the infection rate of HPV 66 increased by 59% compared to the unvaccinated (95% CI: 0.18–0.92). Continuous surveillance is warranted for hrHPV types antigenically distant from vaccine strains, as early type replacement may be emerging. Given the notable difference in effectiveness based on vaccination timing, public-health education should emphasize both the benefits and limitations of HPV vaccination in the context of sexual health.

Avian infectious bronchitis virus (IBV) is a major pathogen impacting the global poultry industry. The QX genotype (GI-19 lineage) of IBV has rapidly spread worldwide and is now the dominant genotype in Asia and Europe. In this study, three QX-type field strains (JS/773, JS/774, and SD/783) were isolated from diseased chicken flocks in eastern China, which had been vaccinated with IBV live attenuated vaccines (H120 or QXL87) between December 2024 and January 2025. Notably, the JS/773 strain showed an H536P mutation at the S protein cleavage site, marking the first identification of a PRRRR cleavage motif in this lineage and highlighting the diversity of cleavage sites among QX-type strains. Recombination analysis showed that these isolates are recombinant variants from vaccine strains 4/91, H120, and QXL87, as well as circulating field strains, with recombination occurring in the ORF1a/ORF1b, ORF5a/ORF5b and M regions. Pathogenicity testing in SPF chickens demonstrated that the isolates induced marked lesions in the respiratory and urinary systems; however, JS/773 caused the most severe tissue damage and resulted in the highest mortality rate among the groups. Cross-neutralization assays revealed substantial antigenic differences between the isolates and the H120 strain, and with reduced antigenic relatedness to the QXL87 strain. Seven amino acid mutations occurred in the isolates S1 subunit neutralizing epitope region, altering protein conformation and potentially contributing to antigenic variation and immune evasion. In conclusion, the genetic traits and pathogenicity of these isolates highlight the evolving QX-type strains in China, that offers new insights into the molecular evolution of QX-type IBV antigenicity.

Background: Fasciola hepatica (F. hepatica) infection reduces antibody avidity to foot-and-mouth disease virus (FMDV) vaccination in cattle despite preserved total antibody levels. However, its effect on vaccine-induced immunity in water buffaloes (Bubalus bubalis), which contribute to FMDV maintenance in endemic settings, has not been investigated. Objectives: To evaluate the effect of natural F. hepatica infection on the magnitude and functional quality of the FMDV–specific antibody response in buffaloes under field conditions. Methods: Two buffalo herds (n = 50 each) were classified by infection status using coproparasitological analysis and serology. All animals were vaccinated within the national foot-and-mouth disease control programme, with the last dose administered 264 days before sampling. Serum neutralising titres, total antibodies by liquid-phase blocking ELISA, IgG levels, and IgG avidity to the A24/Cruzeiro vaccine strain were determined. Results: F. hepatica-infected buffaloes exhibited consistent decreases across all vaccine-induced antibody parameters. Neutralising titres were reduced approximately two-fold, IgG avidity by about 38 percent, IgG levels by about 36 percent, and liquid-phase blocking ELISA titres by about 1.6-fold compared with non-infected animals. Conclusions: This study provides the first field evidence that fasciolosis is associated with changes in the magnitude and quality of vaccine-induced humoral responses following FMDV vaccination in water buffaloes, indicating that F. hepatica infection may influence the interpretation of post-vaccination serological monitoring in this species under endemic field conditions.

Cancer in the cervical region of the uterus is a major health issue for women. A live bacterial vector therapeutic vaccine is genetically engineered to stimulate a targeted immune response by integrating the target antigen gene into a live, attenuated vector. Listeria has become a focal point for bacterial vaccine vectors, owing to its distinctive intracellular parasitism and ability to process and present antigens. Antibiotic-resistant plasmids in vaccines present a dual risk, including the promotion of antibiotic resistance and in vivo instability. The implementation of a balanced lethal system can effectively mitigate both challenges. We constructed therapeutic vaccinations for cervical cancer with dual-species Listeria vectors-attenuated Listeria monocytogenes (LM) with act A/plc B/dal/dat deletion (LM∆∆dd) and recombinant Listeria ivanovii (LI) whose hemolysin gene (ilo) is substituted with the hly gene of LM and with dal/dat deletion (LI∆ilo::hly∆∆dd). Recombinant Listeria-vectored therapeutic vaccines for cervical cancer, expressing HPV6/11/16/18 E6E7 proteins, were constructed based on the balanced lethal system. The basic biological characteristics of the vaccines were described. The vaccinations were evaluated for biosafety, stability, and immunogenicity in mice, and their efficacy was assessed in subcutaneous HPV16/18 E6/E7-expressing tumor models. This study demonstrates that recombinant Listeria expressing multivalent HPV E6/E7 proteins exhibit broad-spectrum anti-tumor effects against cervical cancer models. The study showed that the vaccination strains effectively expressed multivalent HPV antigen, exhibited plasmid stability in vitro, and had no significant impact on biochemical reactions and hemolytic activity. In mice, the vaccine strain was biologically safe, and the plasmid remained stable in vivo. A heterologous immunization strategy-LM prime-LI boost-LM final-was employed to immunize the mice, resulting in a robust, antigen-specific cellular immune response. In the subcutaneous HPV16/18 E6/E7-expressing tumor models, this vaccination protocol achieved complete tumor cure rates of 30% and 40%, respectively, and significantly extended the median survival time. Our objective was to evaluate the efficacy of the vaccine against subcutaneous HPV16/18 E6/E7-expressing tumor models, enhance its safety profile, and co-express multivalent HPV antigens to target a broader range of cervical cancer types.

The present study was carried out to analyze the complete genome sequences of infectious bursal disease virus (IBDV) isolates obtained from field outbreaks in the southern regions of India. Bursal tissue samples were collected and screened by RT-PCR, targeting the VP2 gene. Positive samples were subjected to serological identification via AGID. Following this, eight samples (BGE14, BGE15, MDI14, THI14, EDE14, RPM14, VCN14, and NKL14) were subjected to virus isolation in 9 to 11-day-old embryonated chicken eggs, and their complete genomes were sequenced. Analysis of the VP2 hypervariable region (HVR) revealed that all eight isolates had five unique and highly conserved amino acids (A222, I242, Q249, I256, and S299). However, all the isolates reveal a substitution of Isoleucine by Valine at residue 294 (I294V). Furthermore, analysis of segment B from all Indian IBDV sequences revealed that the triplet amino acid pattern was NEG (residues 145–147) and the amino acid at position 242 was consistently D across all isolates. These findings suggest that segment B of the isolates in this study resembled that of vaccine strains and non-vvIBDV strains. Additionally, the presence of the signature D242 in all Indian isolates, characteristic of non-vvIBDV strains, implies a potential attenuation. Moreover, in the phylogenetic analysis of VP2-HVR, all isolates clustered with very virulent reference strains, while segment B clustered with classical attenuated strains. Notably, the phylogenetic analysis of VP2-HVR and VP1 of these viruses demonstrated genetic variances, suggesting evolutionary changes in segment B across all eight Indian isolates, likely indicative of natural genome reassortment resulting in these specific outbreaks in the flocks.

Live attenuated chicken embryo origin (CEO) vaccines against infectious laryngotracheitis virus (ILTV) are commonly used in long-lived chickens in Australia and generally provide good protection when administered by eye drop (ED). Although vent brush (VB) vaccination provides excellent protection, the associated immune responses are not well characterised. This study compared vaccine-mediated protection conferred by SA2 ILTV vaccine strain administered via ED or VB to 4-week-old layer chicks against a virulent (Class 9) challenge two weeks after vaccination. No significant differences in ILTV DNA in choanal swabs were observed between vaccinated-challenged and non-challenged groups from 4 to 11 days post-challenge (DPC), indicating that both VB and ED vaccination prevented increases in viral load after challenge, although neither prevented infection. Both vaccination routes resulted in high protection indices against clinical signs after challenge (VB, 99%; ED, 90%) and pathological lesion scores in conjunctiva (VB, 83%; ED, 74%) and trachea (VB, 78%; ED, 69%). The non-vaccinated challenged group exhibited significant over-expression of complement component 5a receptor 1, interleukin 1 beta, interleukin 6, myxovirus resistance 1 (MX1), and signal transducer and activator of transcription 1 (STAT1) in both conjunctiva and trachea at DPC 4, whereas ED- and VB-vaccinated challenged groups displayed similar gene expression profiles, resembling those of vaccinated non-challenged group except for elevated MX1 expression at DPC 4 and 7, and STAT1 expression at DPC 4 in the trachea. In conclusion, VB and ED vaccination conferred equivalent clinical protection with gene expression profiles similar to vaccinated, non-challenged chickens, indicating comparable immunological efficacy.

African swine fever (ASF) is an important disease of swine currently affecting pig production worldwide. Vietnam is, currently, the only country where commercial live attenuated vaccines are being freely used in the field. One of these vaccines is based in the use of the ASFV-G-ΔI177L strain, a recombinant virus developed by a partial deletion in the I177L gene from the highly virulent parental strain Georgia 2010. The commercial version of the vaccine was originally limited to use in pigs between 8 and 10 weeks of age, which significantly restricts its use. In this report, we demonstrate that pigs can be vaccinated as early as the fourth week of age, producing an efficacious immune response that fully protects the animals against the challenge with the virulent Vietnamese field strain TTKN/ASFV/DN/2019 and thus increasing the vaccine's usage to pigs 4-10 weeks of age. Several groups of four-week-old pigs were intramuscularly (IM) vaccinated with a single dose of a commercial vaccine containing 102.6 HAD50 of ASFV-G-ΔI177L and IM challenged 28 days later with 102 HAD50 of TTKN/ASFV/DN/2019. All the vaccinated animals remained clinically normal after vaccination, demonstrating no presence of residual virulence of ASFV-G-ΔI177L in animals of this age. In addition, all vaccinated animals remained protected after the challenge, showing no clinical signs associated with ASF during the observational period. These results corroborate the safety and efficacy of the ASFV-G-ΔI177L vaccine strain when used in pigs as early as four week of age.

Transcriptomic analysis of Crandell-Rees feline kidney cell infections with field and vaccine feline calicivirus strains.

We characterized influenza A(H1N1)pdm09, A(H3N2), and B/Victoria viruses circulating in Japan during 2023–2024, focusing on lineage placement relative to WHO-recommended vaccine strains and on baloxavir resistance (PA/I38T substitutions). We enrolled 210 outpatients with influenza-like illness across eight clinics in six prefectures (October 2023–September 2024). Of these, 209 had an analyzable pre-treatment respiratory specimen for RT-PCR; hemagglutinin (HA) and neuraminidase (NA) genes were sequenced by next-generation sequencing (NGS). PA/I38T substitutions that confer baloxavir resistance were assessed by cycling-probe RT-PCR, Sanger sequencing, and NGS. HA phylogenies were constructed with global datasets and WHO vaccine reference strains. Of 209 pre-treatment specimens, 181 were influenza-positive (A(H1N1)pdm09 44.2%, A(H3N2) 37.6%, B/Victoria 18.2%); 51 follow-up specimens were collected ≈4–5 days after baloxavir or neuraminidase inhibitor therapy. HA phylogeny placed A(H1N1)pdm09 in clades 5a.2a/5a.2a.1 with predominance of subclade D.2. A(H3N2) clustered exclusively in clade 2a.3a.1 (J lineage, mostly J.1), indicating a mismatch with the season’s A/Darwin/9/2021 vaccine component and supporting the subsequent J-lineage update. All B/Victoria genomes fell within V1A.3a.2 on a C.5 backbone (C.5.1 and C.5.7). No PA/I38T variant was detected in any pre-treatment specimen. Post-baloxavir, PA/I38T emerged in one A(H3N2) case (confirmed by all three methods) and in one B/Victoria case detected by NGS only (minority variant in a low-load sample). NA genes showed no substitutions associated with reduced susceptibility to laninamivir (e.g., E119A, G147E). During 2023–2024, A(H1N1)pdm09 and B/Victoria remained genetically aligned with their vaccine components, whereas A(H3N2) shifted to the J lineage, consistent with the 2024–2025 vaccine update. Although pre-treatment PA/I38T was absent, low-frequency on-therapy selection was observed, including a rare PA/I38T in influenza B/Victoria detected by NGS, suggesting the value of deep sequencing when viral loads are low. These integrated genomic–clinical data support vaccine strain realignment for H3N2 and continued monitoring of baloxavir resistance in outpatient care.

BackgroundThe Bacille Calmette-Guérin (BCG) vaccine, developed in the early 20th century, remains the only widely approved prophylactic against tuberculosis (TB). It was derived from an attenuated strain of Mycobacterium bovis. Its protective efficacy against pulmonary TB in adolescents and adults varies from 0 to 80%; genetic differences among worldwide vaccine strains contribute to this variation. The Brazilian vaccine strain used until 2017, BCG Moreau, is considered a primitive strain and more immunogenic, closer to the original BCG when compared to newer strains, such as BCG Pasteur. The characterization of BCG daughter-strains can contribute not only to a better understanding of the vaccine and its protective effect, but also to elucidating how different BCG culture conditions may contribute to the impact on the host’s immune response. Thus, we aimed to characterize the differences in gene expression through the intracellular proteomic profile of BCG Moreau and Pasteur strains, cultivated in Sauton or 7H9 media, using two-dimensional electrophoresis (2DE) and mass spectrometry.ResultsComparative 2DE analysis of 7H9-cultured BCG strains showed 7 upregulated proteins in BCG Pasteur versus only 2 in BCG Moreau. This profile, however, was different for cultures obtained in the Sauton media, in which 6 proteins were upregulated in BCG Moreau compared to only 3 in BCG Pasteur. The comparison of 2DE profiles from the same strain under these 2 cultivation forms revealed that BCG Moreau regulates 19 proteins when grown in Sauton media, with 17 upregulated, while BCG Pasteur modulated the expression of 10 proteins, 7 upregulated when compared to growth in 7H9. These findings might indicate that the BCG Moreau strain needs to regulate its protein composition more strongly than Pasteur to adapt to adverse conditions of growth and cultivation.ConclusionsThe analysis of the intracellular 2DE profile reveals differences between cultivation methods as well as between the two M. bovis BCG vaccine strains, Moreau and Pasteur. Our results identify important proteins that may contribute to elucidating differences in vaccine efficacy, highlighting the importance of culture conditions when comparing different studies. These findings contribute to the characterization of the Brazilian vaccine strain, BCG Moreau under growth conditions similar to those used in vaccine production.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12866-025-04529-9.

Highly pathogenic avian influenza (HPAI) H5N8 virus, first identified in late 2016 in Egypt, continues to circulate and has replaced the previously dominant HPAI H5N1 virus of clade 2.2.1. In this study, HPAI H5N8 was detected on 23 commercial poultry farms in Egypt. Complete genome sequences of three isolates collected in 2021 were obtained using next-generation sequencing (NGS) and subjected to genetic characterization. Phylogenetic analysis showed these isolates to belong to clade 2.3.4.4b, comprising two genotypes: EA-2021-Q and EA-2020-A. Molecular analysis of the haemagglutinin (HA) protein revealed the presence of T156A and V538A substitutions in the duck isolate and an N183S substitution in the chicken isolate. Several additional nonsynonymous mutations were identified, including 147I and 504V in the PB2 protein, 127V, 672L, and 550L in the PA protein, 64F and 69P in the M2 protein, and 42S in the NS1 protein. Comparative analysis of HA antigenic sites between these isolates and the human vaccine against H5N8 revealed four nonsynonymous mutations: S141P, A154N, D45N, and V174I. Notably, the HA sequences of the studied isolates shared 98.7-99.4% amino acid sequence identity, and the NA sequences shared 96.1-97.1% identity to those of the 2.3.4.4b candidate human H5N8 vaccine strain (CVV) A/Astrakhan/3212/2020-like. These findings underscore the importance of continuous monitoring of the genetic evolution of avian influenza viruses to guide updates of candidate vaccine strains. Furthermore, the high similarity between the detected isolates and a zoonotic Russian H5N8 wild-type strain highlights the potential risk of cross-species transmission and possible human infection.

In 2025, measles cases in the United States have reached their highest level since the disease was officially declared eliminated in 2000. Molecular assays may assist in the early diagnosis of measles and improve contact tracing efforts. In this manuscript, we describe the validation of a real-time PCR assay on the Hologic Panther Fusion Open Access system for the detection of measles virus (MeV) and differentiation between wild-type and vaccine strains. After implementation, we examined 3 months of clinical testing data to understand testing trends and utilization. Over the study period, a total of 525 tests from 491 patients were performed. MeV was detected in 16 specimens with 6 wild-type and 10 vaccine strain identifications. Children less than 10 years old constituted the largest proportion of tested individuals (54.3%) and vaccine strain detections (9/10, median age 1.2 years), while wild-type infections were observed in individuals aged 20-50 (6/6, median age 32.6 years). Those with vaccine strain detected had significantly higher Ct values for the pan-measles target versus wild-type infections (33.6 vs 28.3; P-value < 0.05). Only 4.2% of patients in our cohort received paired serologic and molecular measles testing. When paired data were available, PCR had a positive agreement of 25% and a negative agreement of 98% with IgM results. Molecular testing for MeV with the ability to differentiate wild-type strains from vaccine strains is a helpful tool in the response to measles re-emergence.IMPORTANCEThe 2025 U.S. measles outbreak comes at a challenging time for public health in America. As vaccine hesitancy increases and resources are withdrawn from national and state public health laboratories, historically low incidence diseases develop into nationwide outbreaks that require increased testing capacity. In response to this need, our national reference laboratory developed a measles PCR assay that allows for the detection and separation of vaccine from wild-type strains. The assay was launched on the Hologic Panther fusion system to improve throughput and reduce turnaround times. In this research article, we describe the design of our assay, validation results, and early clinical performance.

Development and applications of an inactivated pigeon paramyxovirus type I in which the F gene was replaced with the LaSota F gene.

Yellow fever virus (YFV), a mosquito-borne Orthoflavivirus, remains a significant public health concern, especially in regions with low vaccine coverage. Since 2010, yellow fever vaccination is not recommended for breastfeeding women due to reported cases of vaccine strain transmission through breast milk causing neonatal meningoencephalitis. However, breastfeeding transmission efficiency of the vaccine strains remains unknown, and wild-type strains transmission has been suggested following viral RNA detection in milk. Obtaining direct evidence of breastfeeding-related transmission in humans is challenging as vector-borne exposure confounds analyses, making animal models essential for assessing this risk. We used A129 mouse model to investigate YFV transmission via breastfeeding for wild-type and vaccine strains, and human epithelial in vitro models to explore mechanisms of mammary and intestinal barrier crossing. Wild-type and vaccine strains spread to mammary glands, targeting mainly stromal and immune cells, and are excreted into milk as free and cell-associated virus. In vitro, mammary epithelial cells also support infection, suggesting two mechanisms of epithelial crossing. Neonates are susceptible to oral infection, showing higher infection rates for wild-type virus but evidence of neuroinvasion for both strains. These strains infect and cross an in vitro human intestinal barrier model, suggesting this epithelium as a potential viral entry site for neonates. Finally, the virus can be transmitted from infected dams to suckling pups via breastfeeding, though rarely. This study demonstrates YFV transmission through breastfeeding in an animal model and supports the biological plausibility of this route, highlighting its potential among YFV transmission risks.

Canine distemper virus (CDV, species Morbillivirus canis) is a highly contagious pathogen with a broad host range among carnivores. In common with measles virus, alveolar macrophages (AMs) are among the first target cells of infection in the respiratory tract. Therefore, in vitro infections of primary canine AMs were performed with the attenuated Onderstepoort (Ond) and field R252 strain of CDV over a period of 6 days. This showed that AMs are permissive to CDV infection and that such infections are productive with respect to the release of new virus particles. Phenotypic differences were observed over the entire course of the experiment, as higher levels of infection and virus production were observed in CDV R252-infected AMs, while infection with CDV Ond resulted in more prominent cytopathic effects, including syncytium formation. Transcriptome analyses of samples from 1 day post-infection via total RNA sequencing demonstrated further marked differences with respect to the pro-inflammatory response and cell death pathways. CDV Ond-infected AMs exhibited robust induction of pro-inflammatory mediators including type I interferon-related signaling pathways, whereas CDV R252-infected cells showed much weaker expression of these pathways. These transcriptomic differences were further highlighted by the detection of the highest rates of cell apoptosis and lactate dehydrogenase activity in the supernatants of CDV Ond-infected AM cultures over the entire course of the experiment. In addition, transcriptome differences indicate disturbances of homeostatic AM functions associated with CDV infection. These results provide insights into early events in the pathogenesis of CDV infection and mechanisms underlying vaccine strain attenuation.IMPORTANCEMorbilliviruses, including canine distemper virus (CDV) and human measles virus, cause severe systemic disease with respiratory distress, immunosuppression, and neurologic signs. While natural infection in dogs has become rare due to efficient vaccination, outbreaks in wildlife populations can be devastating, and concerns about zoonotic potential of CDV have been raised. The impact of CDV infection on the transcriptome of alveolar macrophages has not been elucidated thus far. Knowledge about early events in CDV pathogenesis and phenotypic consequences of vaccine attenuation is therefore necessary to protect endangered wildlife populations and might furthermore serve as a model for human measles. This study presents the first transcriptomic analyses of primary AMs during the initial phase of morbillivirus infection. These results provide insights into early events in the pathogenesis of CDV infection and mechanisms serving to restrict the spread of an attenuated virus strain.

The strategy of specific prophylaxis of plague for epidemic indications accepted in the Russian Federation, while having positive experience, needs to be improved. The solution to one of the problems is the use of vaccines together with adjuvants. The ability of the selenium-containing preparation 974zh to increase the immunogenicity of live plague vaccine was demonstrated. The aim of the work. To evaluate the subpopulation composition of blood cells in animals immunized by Y. pestis EV on the background of immunomodulation. Materials and methods. In the study we used 100 white mice. Blood served as a material for the study. The phenotype of lymphocytes was determined on a flow cytofluorimeter using antibodies to markers CD45, CD44, CD3, CD19, CD4, CD8, CD25, CD62L, I-A/I-E (MHC II). Results. Evaluation of cellular immunity revealed a statistically significant increase in monocytes on day 7 and a decrease in lymphocytes on day 3 in mice immunized with Y. pestis EV at doses of 10 3 CFU and 10 4 CFU in combination with 974zh. When co-injected with Y. pestis EV (103 CFU) and 974zh, unlike Y. pestis EV at different doses, no decrease in CD3 + CD4 + CD8 - CD25 + cells was detected. Conclusion. Thus, the adjuvant property of 974zh has been established, contributing to an increase in the immunogenic properties of the Y. pestis EV vaccine strain, regardless of the dose. The use of Y. pestis EV at a dose of 10 3 CFU to reduce the bacterial load is appropriate.