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Countermeasures against Zika virus (ZIKV) epidemics are urgently needed. In this study we generated a ZIKV virus-like particle (VLP) based vaccine candidate and assessed the immunogenicity of these particles in mice. The ZIKV-VLPs were morphologically similar to ZIKV by electron microscopy and were recognized by anti-Flavivirus neutralising antibodies. We observed that a single dose of unadjuvanted ZIKV-VLPs, or inactivated ZIKV, generated an immune response that lasted over 6 months, but did not neutralize ZIKV infection of cells in vitro. However, when we co-administered the ZIKV VLPs with either Aluminium hydroxide (Alhydrogel®; Alum), AddaVax or Pam 2 Cys we observed that Alum was the most effective in a single dose regime, since it not only produced antibodies that neutralized the virus, but also generated a greater number of antigen-specific memory B cells. We additionally observed that the generation of the neutralising antibodies persisted for up to 6 months. Our results suggest that a single dose ZIKV VLPs could be a suitable single dose vaccine candidate for use in outbreak settings., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Chronic hepatitis C virus (HCV) infection represents a major health threat to global population. In India, approximately 15-20% of cases of chronic liver diseases are caused by HCV infection. Although, new drug treatments hold great promise for HCV eradication in infected individuals, the treatments are highly expensive. A vaccine for preventing or treating HCV infection would be of great value, particularly in developing countries. Several preclinical trials of virus-like particle (VLP) based vaccine strategies are in progress throughout the world. Previously, using baculovirus based system, we have reported the production of hepatitis C virus-like particles (HCV-LPs) encoding structural proteins for genotype 3a, which is prevalent in India. In the present study, we have generated HCV-LPs using adenovirus based system and tried different immunization strategies by using combinations of both kinds of HCV-LPs with other genotype 3a-based immunogens. HCV-LPs and peptides based ELISAs were used to evaluate antibody responses generated by these combinations. Cell-mediated immune responses were measured by using T-cell proliferation assay and intracellular cytokine staining. We observed that administration of recombinant adenoviruses expressing HCV structural proteins as final booster enhances both antibody as well as T-cell responses. Additionally, reduction of binding of VLP and JFH1 virus to human hepatocellular carcinoma cells demonstrated the presence of neutralizing antibodies in immunized sera. Taken together, our results suggest that the combined regimen of VLP followed by recombinant adenovirus could more effectively inhibit HCV infection, endorsing the novel vaccine strategy., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: The recombinant yellow fever-17D-dengue virus, live, attenuated, tetravalent dengue vaccine (CYD-TDV) has undergone extensive clinical trials. Here safety and consistency of immunogenicity of phase III manufacturing lots of CYD-TDV were evaluated and compared with a phase II lot and placebo in a dengue-naïve population., Methods: Healthy 18-60 year-olds were randomly assigned in a 3:3:3:3:1 ratio to receive three subcutaneous doses of either CYD-TDV from any one of three phase III lots or a phase II lot, or placebo, respectively in a 0, 6, 12 month dosing schedule. Neutralising antibody geometric mean titres (PRNT50 GMTs) for each of the four dengue serotypes were compared in sera collected 28 days after the third vaccination-equivalence among lots was demonstrated if the lower and upper limits of the two-sided 95% CIs of the GMT ratio were ≥0.5 and ≤2.0, respectively., Results: 712 participants received vaccine or placebo and 614 (86%) completed the study; 17 (2.4%) participants withdrew after adverse events. Equivalence of phase III lots was demonstrated for 11 of 12 pairwise comparisons. One of three comparisons for serotype 2 was not statistically equivalent. GMTs for serotype 2 in phase III lots were close to each other (65.9, 44.1 and 58.1, respectively)., Conclusions: Phase III lots can be produced in a consistent manner with predictable immune response and acceptable safety profile similar to previously characterised phase II lots. The phase III lots may be considered as not clinically different as statistical equivalence was shown for serotypes 1, 3 and 4 across the phase III lots. For serotype 2, although equivalence was not shown between two lots, the GMTs observed in the phase III lots were consistently higher than those for the phase II lot. As such, in our view, biological equivalence for all serotypes was demonstrated., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Infection with dengue virus is a major public health problem in the Asia-Pacific region and throughout tropical and sub-tropical regions of the world. Vaccination represents a major opportunity to control dengue and several candidate vaccines are in development. Experts in dengue and in vaccine introduction gathered for a two day meeting during which they examined the challenges inherent to the introduction of a dengue vaccine into the national immunisation programmes of countries of the Asia-Pacific. The aim was to develop a series of recommendations to reduce the delay between vaccine licensure and vaccine introduction. Major recommendations arising from the meeting included: ascertaining and publicising the full burden and cost of dengue; changing the perception of dengue in non-endemic countries to help generate global support for dengue vaccination; ensuring high quality active surveillance systems and diagnostics; and identifying sustainable sources of funding, both to support vaccine introduction and to maintain the vaccination programme. The attendees at the meeting were in agreement that with the introduction of an effective vaccine, dengue is a disease that could be controlled, and that in order to ensure a vaccine is introduced as rapidly as possible, there is a need to start preparing now., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Japanese encephalitis chimeric virus vaccine (JE-CV) was developed to replace licensed mouse brain-derived vaccine (MBD-JE), the production of which ceased in 2005. Two randomised controlled phase 3 studies were conducted. Immunogenicity study: 410 participants received one JE-CV injection, 410 received 3 MBD-JE injections. Safety study: 1,601 participants received JE-CV, 403 received placebo. Seroconversion after a single JE-CV vaccination (99.1%) was statistically non-inferior to that after three-dose MBD-JE (95.1%) vaccination. JE-CV elicited a rapid immune response, with 93.6% of participants seroconverting within 14 days. Adverse reaction rates were significantly lower with JE-CV (67.6%) than with MBD-JE (82.2%) (p<0.001), and the reactogenicity profile of JE-CV was comparable with that of placebo. A single dose of JE-CV elicited rapid seroconversion in a higher proportion of vaccinees than the current vaccine with fewer reactions. The safety profile of JE-CV is good., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Vaccine preventable diseases (VPDs) threaten international travelers, but little is known about their epidemiology in this group. We analyzed records of 37,542 ill returned travelers entered into the GeoSentinel Surveillance Network database. Among 580 (1.5%) with VPDs, common diagnoses included enteric fever (n=276), acute viral hepatitis (n=148), and influenza (n=70). Factors associated with S. typhi included VFR travel (p<0.016) to South Central Asia (p<0.001). Business travel was associated with influenza (p<0.001), and longer travel with hepatitis A virus (p=0.02). 29% of those with VPDs had pre-travel consultations. At least 55% of those with VPDs were managed as inpatients, compared to 9.5% of those with non-VPDs. Three deaths occurred; one each due to pneumococcal meningitis, S. typhi, and rabies. VPDs are significant contributors to morbidity and potential mortality in travelers. High rates of hospitalization make them an attractive target for pre-travel intervention., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Effective CD8(+) T cell responses have been induced using totally synthetic self-adjuvanting lipopeptides containing the dipalmitoyl-S-glyceryl cysteine lipid moiety, which is a ligand for Toll-like receptor 2 (TLR2) on dendritic cells (DC). In this study, we evaluated the use of lipopeptide vaccine candidates containing HLA-A2-restricted epitopes for DC-based immunotherapy of HCV infection. Lipopeptides were able to induce specific CD8(+) T cell responses in HLA-A2 transgenic mice and consistently activated human monocyte-derived DC from both healthy individuals and HCV infected patients. Lipopeptide-pulsed human DC were also found to secrete the pro-inflammatory cytokine IL-12p70 and were able to activate antigen-specific IFN-gamma production by autologous CD8(+) T cells obtained from a hepatitis C patient. These results show that DC from HCV patients can be matured and antigen loaded with TLR2-targeting lipopeptides for effective presentation of CD8(+) T cell epitopes; the use of autologous lipopeptide-pulsed DC or direct lipopeptide vaccination may be successful approaches for the priming or boosting of anti-HCV CD8(+) T cell responses to aid in the clearance of the virus in chronically infected individuals.

Background: Increased travel to exotic destinations around the world is escalating the risk of exposure to animal-associated injuries with a risk of acquiring rabies., Methods: We have examined data reported to GeoSentinel Surveillance Network to highlight characteristics of animal-associated injuries in travellers., Results: A total of 320 cases were reported from 1998 to 2005. Travellers were predominantly tourists from developed countries with median travel duration of 23 days. A pre-travel encounter was recorded in 45.0% of the cases. A significantly greater proportion of patients with animal-related injuries were female compared to other travel associated diagnosis (54.7% versus 47.4%) and were most likely patients aged <15 years (6.2% versus 2.6%). The proportionate morbidity for sustaining an animal bite was higher among travellers visiting Southeast Asia (3.9%) and the rest of Asia (2.2%) compared to Australia-New Zealand (1.9%), Africa (1.0%), Latin America (0.8%), North America (0.9%) and Europe (1.2%). Seventy-five percent of cases occurred in countries endemic for rabies. Dogs were involved in 51.3% of cases, monkeys in 21.2%, cats in 8.2%, bats in 0.7% and humans in 0.7%. The higher likelihood for animal-related injuries among female travellers was dependant on the animal species involved, with monkeys accounting for the majority of injuries. In contrast, males were more likely to be injured by dogs. Only 66.1% of all patients reported with animal-related injury received rabies post-exposure prophylaxis., Conclusions: This data shows that animal-associated injuries are not uncommon among returned travellers presenting to GeoSentinel sites. The highest proportion of injuries was recorded in travellers to Asia, mostly in regions, which are endemic for rabies, and this had led to a requirement for PEP.