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Objective: Low pathogenic avian influenza (LPAI) subtype H9N2 and Newcastle disease (ND) are the two major economic diseases worldwide. Continuous genetic evolution of both viruses raises concerns about potential vaccine failure under field conditions. The efficacy of commercially available bivalent inactivated vaccines in preventing ND and avian influenza subtype H9N2 in Bangladesh has not been comprehensively assessed. This study aimed to contribute crucial insights into the evaluated vaccine’s performance against local field strains and to contribute novel data to optimize poultry vaccination strategies in endemic regions. Materials and Methods: The experimental birds were divided into several groups and were vaccinated according to the manufacturer’s recommendation. Serum samples were collected at regular intervals. Antibody levels against H9N2 and ND virus (NDV) were assessed using hemagglutination inhibition and enzyme-linked immunosorbent assay tests, targeting each virus individually. Following the final booster dose, vaccinated and unvaccinated groups were challenged with locally circulating NDV and H9N2 AI virus strains. Results: Vaccinated chickens developed robust antibody responses, with titers progressively increasing after each booster and peaking following the final dose. Upon challenge with circulating strains of NDV and H9N2, the immunized birds exhibited no clinical signs of disease. Moreover, no detectable viral shedding of H9N2 was observed, and only minimal NDV shedding was detected in the vaccinated groups. Conclusion: Our study revealed that all three bivalent inactivated vaccines are effective against LPAI and ND in poultry and elicit a quick and robust antibody response.

Background/Objectives: Nocardia seriolae and Aeromonas veronii are two important pathogens that can affect a wide range of fish species and cause substantial economic losses. However, a vaccine that simultaneously protects fish from these two bacterial infections is not yet available. Methods: Three formalin-inactivated whole-cell vaccines prepared from N. seriolae and A. veronii (Monovalent Av, Monovalent Ns and Bivalent Av-Ns) were generated, and their efficacy was evaluated through a range of tests. The immune-related gene expression in the spleen and head kidney, enzyme activity, and specific antibody levels in serum were also detected. Results: All groups of vaccinated fish exhibited increased serum enzymatic activity compared with control fish, which peaked at week 3 after vaccination; in particular, that of the Bivalent Av-Ns group increased remarkably. The expression of immune-related genes in the spleen, head, and kidneys increased after immunization and were significantly enhanced (p < 0.05) in the bivalent vaccine group. Specific antibodies were produced at the 1st wpv, peaked at the 4th to the 5th wpv, and then decreased at the 6th wpv in all vaccinated groups. The Monovalent Av and Monovalent Ns against A. veronii and N. seriolae showed 56.67% and 22.22% RPS, respectively. Moreover, Bivalent Av-Ns offered 33.33% and 76.67% RPS for single infection with N. seriolae or A. veronii, as well as providing 44.44% RPS for dual infection with combined N. seriolae and A. veronii. Conclusions: Our findings indicate that the administration of the A. veronii and N. seriolae bivalent vaccine can protect largemouth bass from both bacterial infections.

The Aeromonas salmonicida is responsible for causing furunculosis in various fish species. Furunculosis is a ubiquitous disease that affects the aquaculture industry and causes the mass mortality of turbot. Vibrio vulnificus is a pathogen that causes skin ulcers and hemorrhagic septicemia in fish, resulting in significant mortality in aquaculture. In this study, we have established a bivalent inactivated vaccine against A. salmonicida and V. vulnificus with Montanide™ ISA 763 AVG as an adjuvant. This bivalent inactivated vaccine was used to immunize turbot by intraperitoneal injection, and the relevant immune indexes were detected. The results demonstrate that the bivalent inactivated vaccine exhibited a relative percent survival (RPS) of 77% following A. salmonicida and V. vulnificus intraperitoneal challenge. The vaccinated group exhibited higher levels of acid phosphatase activity and lysozyme activity compared to the control group. ELISA results showed a significant increase in serum antibody levels in immunized turbot, which was positively correlated with immunity. In the kidney tissue, related immune genes (TLR5, CD4, MHCI and MHCII) were up-regulated significantly, showing that the vaccine can induce cellular and humoral immune responses in turbot. In conclusion, the bivalent inactivated vaccine against A. salmonicida and V. vulnificus was immunogenic, efficiently preventing turbot from infection, which has the potential to be applied in aquaculture.

Vibrio scophthalmi and Aeromonas salmonicida can cause high turbot mortality and huge economic losses. Presently, vaccination is the most promising method for preventing communicable diseases. In this study, we used formalin to kill V. scophthalmi and A. salmonicida cells, and mixed with the mineralized oil adjuvant (Montanide™ ISA 763 AVG) to prepare the bivalent inactivated vaccine. The results showed that turbot inoculated with the bivalent inactivated vaccine exhibited strong tolerance to the infection of V. scophthalmi and A. salmonicida , and no obvious clinical symptoms and pathological changes were observed. The activities of enzymes lysozyme, acid phosphatase and complement C3 had significantly increased after the vaccination. The antibody titer response of vaccinated turbot was greatly boosted, which was positively connected with the immunological impact according to ELISA results. Simultaneously, the expression levels of immune-related genes such as MHC-IIα, MHC-IIβ, CD4, CD8, TNF-α and IL-1β were up-regulated, demonstrating that it might stimulate humoral and cellular immunological response in turbot. These findings highlight the potential of the bivalent inactivated vaccine for controlling V. scophthalmi and A. salmonicida infections in turbot.

In 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) recommended introduction of at least one inactivated poliovirus vaccine (IPV) dose in essential immunization programs. We evaluated systemic humoral and intestinal mucosal immunity of a sequential IPV-bivalent oral poliovirus vaccine (bOPV) schedule compared with a co-administration IPV + bOPV schedule in an open-label, randomized, controlled, non-inferiority, inequality trial in Dhaka, Bangladesh. Healthy infants aged 6 weeks were randomized to either: (A) IPV and bOPV at 6 and bOPV at 10 and 14 weeks (IPV + bOPV-bOPV-bOPV); or (B) IPV at 6 and bOPV at 10 and 14 weeks (IPV-bOPV-bOPV). Of 456 participants enrolled and randomly assigned during May–August 2015, 428 (94%) were included in the modified intention-to-treat analysis (arm A: 211, arm B: 217). Humoral immune responses did not differ at 18 weeks between study arms: type 1 (98% versus 96%; p = 0.42), type 2 (37% versus 39%; p = 0.77), and type 3 (97% versus 93%; p = 0.07). Virus shedding one week after the bOPV challenge dose in arm B was non-inferior to arm A (type 1 difference = −3% [90% confidence interval: −6 − 0.4%]; type 3 difference: −3% [−6 to −0.2%]). Twenty-six adverse events including seven serious adverse events were reported among 25 participants including one death; none were attributed to study vaccines. An IPV-bOPV-bOPV sequential schedule induced comparable systemic humoral immunity to all poliovirus types and types 1 and 3 intestinal mucosal immunity as an IPV + bOPV-bOPV-bOPV co-administration schedule.

Efficacy and safety of a two-dose regimen of bivalent killed whole-cell oral cholera vaccine (Shantha Biotechnics, Hyderabad, India) to 3 years is established, but long-term efficacy is not. We aimed to assess protective efficacy up to 5 years in a slum area of Kolkata, India. In our double-blind, cluster-randomised, placebo-controlled trial, we assessed incidence of cholera in non-pregnant individuals older than 1 year residing in 3933 dwellings (clusters) in Kolkata, India. We randomly allocated participants, by dwelling, to receive two oral doses of modified killed bivalent whole-cell cholera vaccine or heat-killed Escherichia coli K12 placebo, 14 days apart. Randomisation was done by use of a computer-generated sequence in blocks of four. The primary endpoint was prevention of episodes of culture-confirmed Vibrio cholerae O1 diarrhoea severe enough for patients to seek treatment in a health-care facility. We identified culture-confirmed cholera cases among participants seeking treatment for diarrhoea at a study clinic or government hospital between 14 days and 1825 days after receipt of the second dose. We assessed vaccine protection in a per-protocol population of participants who had completely ingested two doses of assigned study treatment. 69 of 31 932 recipients of vaccine and 219 of 34 968 recipients of placebo developed cholera during 5 year follow-up (incidence 2·2 per 1000 in the vaccine group and 6·3 per 1000 in the placebo group). Cumulative protective efficacy of the vaccine at 5 years was 65% (95% CI 52–74; p<0·0001), and point estimates by year of follow-up suggested no evidence of decline in protective efficacy. Sustained protection for 5 years at the level we reported has not been noted previously with other oral cholera vaccines. Established long-term efficacy of this vaccine could assist policy makers formulate rational vaccination strategies to reduce overall cholera burden in endemic settings. Bill & Melinda Gates Foundation and the governments of South Korea and Sweden.

Continuous boosting with the original vaccines based on the Ancestral (Wuhan hu-1) strain to maintain immunity has not been sufficient to detain the emergence and rapid dissemination of viral variants. This study was to evaluate the immune responses and safety of a heterologous boost with bivalent Original/Omicron BA.4–5 vaccine mRNA vaccine given after at least 12 months to those who had been primed with NDV-HXP-S COVID -19 vaccine (an inactivated recombinant Newcastle disease virus vaccine). An open-label study assessing the booster effects of the bivalent mRNA vaccine given to those who were primed with two doses of the NDV-HXP-S COVID-19 vaccine (either 3 μg with or without the CpG1018 adjuvant or 10 μg of NDV-HXP-S) at least one year ago. The immune responses were measured accordingly. The bivalent mRNA boost was safe. Corresponding geometric mean fold rise (GMFRs) in NT50 against Ancestral strain at D28 were 4.4, 3.3, and 3.6 and further increased to 7.8, 6.6 and 6.3 by D90 in the 3 μg, 3 μg + CpG and 10 μg dose groups, respectively. In contrast, the GMFR NT50 against XBB.1.5 peaked at D28 to 11.8, 11.3 and 8.4 and declined to 3.3, 4.0 and 2.6 at D90 in the three dose groups, respectively. Regarding the IFN-gamma response, the group primed with 3 μg + CpG had a greater T cell response by D90 than the other two groups. There was a trend in higher NT50 against XBB.1.5 after boosting, especially among participants in the hybrid-immune subgroup who had a SARS-CoV-2 infection more than 12 months. No safety concerns reported. The immune responses stimulated by the heterologous boost with bivalent mRNA vaccine in the NDV-HXP-S primed groups were high especially among the hybrid immune subgroup. Thai Clinical Trial Registry: WHO REGISTRY PLATFORM- TCTR20230809003. •NDV-HXP-S COVID-19 vaccines previously demonstrated as a good priming vaccine.•The first results of the bivalent mRNA COVID-19 vaccine booster given to those who were primed with two doses of the NDV-HXP-S COVID-19 vaccine.•The immune responses (neutralizing antibodies, anti-Spike IgG, and IFN-γ response) stimulated by the heterologous boost with the bivalent mRNA vaccine in the NDV-HXP-S-primed groups were high, especially among the hybrid immune subgroup.

Background. We evaluated the herd protection conferred by an oral cholera vaccine using 2 approaches: cluster design and geographic information system (GIS) design. Methods. Residents living in 3933 dwellings (clusters) in Kolkata, India, were cluster-randomized to receive either cholera vaccine or oral placebo. Nonpregnant residents aged ≥1 year were invited to participate in the trial. Only the first episode of cholera detected for a subject between 14 and 1095 days after a second dose was considered. In the cluster design, indirect protection was assessed by comparing the incidence of cholera among nonparticipants in vaccine clusters vs those in placebo clusters. In the GIS analysis, herd protection was assessed by evaluating association between vaccine coverage among the population residing within 250 m of the household and the occurrence of cholera in that population. Results. Among 107 347 eligible residents, 66 990 received 2 doses of either cholera vaccine or placebo. In the cluster design, the 3-year data showed significant total protection (66% protection, 95% confidence interval [CI], 50%–78%, P < .01) but no evidence of indirect protection. With the GIS approach, the risk of cholera among placebo recipients was inversely related to neighborhood-level vaccine coverage, and the trend was highly significant (P < .01). This relationship held in multivariable models that also controlled for potentially confounding demographic variables (hazard ratio, 0.94 [95% CI, .90–.98]; P < .01). Conclusions. Indirect protection was evident in analyses using the GIS approach but not the cluster design approach, likely owing to considerable transmission of cholera between clusters, which would vitiate herd protection in the cluster analyses. Clinical Trials Registration. NCT00289224.

The immunogenicity and safety of the sequential schedule of Sabin strain-based inactivated poliovirus vaccine (sIPV) and bivalent oral poliovirus vaccine (bOPV) remains poorly understood in Chinese population. A multi-center, open-label, randomized controlled trial was performed involving 648 healthy infants aged 2 months from Inner Mongolia, Shanxi, and Hebei provinces. These participants were divided into three groups: sIPV-bOPV-bOPV, sIPV-sIPV-bOPV, and sIPV-sIPV-sIPV. Doses were administered sequentially at age 2, 3, and 4 months. Neutralisation assays were tested using sera collected at 2 months and 5 months. A total of 569 were included in the per-protocol analysis. The seroconversion rates of poliovirus type 1 and 3 were 100% in all three groups, the seroconversion rate of poliovirus type 2 was 91.53% (173/189) (95% CI: 86.62–95.08) in the sIPV-bOPV-bOPV group, 98.38% (182/185) (95% CI: 95.33–99.66) in the sIPV-sIPV-bOPV group, and 99.49% (194/195) (95% CI: 97.18–99.99) in the sIPV-sIPV-sIPV group. For the seroconversion rate of poliovirus types 1 and 3, the sIPV-bOPV-bOPV and sIPV-sIPV-bOPV groups were non-inferior to the sIPV-sIPV-sIPV group. For the seroconversion rate of poliovirus type 2, the sIPV-sIPV-bOPV group was non-inferior to the sIPV-sIPV-sIPV group, and the sIPV-bOPV-bOPV group was inferior to the sIPV-sIPV-sIPV group. All three groups exhibited good safety, with two serious adverse events reported, that were unrelated to vaccine. In china, a new vaccination schedule that including 2 doses of IPV in the national immunization programs is essential. Trial registration ClinicalTrials.govNCT04054492.

Abstract In May 2016, countries using oral polio vaccine for routine immunization switched from trivalent oral poliovirus vaccine (tOPV) to bivalent type 1 and 3 OPV (bOPV). This was done in order to reduce risks from type 2 vaccine-derived polioviruses (VDPV2) and vaccine-associated paralytic poliomyelitis (VAPP) and to introduce ≥1 dose of inactivated poliovirus vaccine (IPV) to mitigate post-switch loss of type 2 immunity. We conducted a literature review of studies that assessed humoral and intestinal immunogenicity induced by the newly recommended schedules. Differences in seroconversion rates were closely associated with both timing of first IPV administration and number of doses administered. All studies demonstrated high levels of immunity for types 1 and 3 regardless of immunization schedule. When administered late in the primary series, a second dose of IPV closed the humoral immunity gap against polio type 2 associated with a single dose. IPV doses and administration schedules appear to have limited impact on type 2 excretion following challenge.