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1.
Pan Afr Med J ; 47: 120, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38828420

RESUMEN

Introduction: Aedes albopictus, like Aedes aegypti, is a virulent vector of arboviruses especially the well-documented spread of yellow fever around the world. Although yellow fever is prevalent in Nigeria, there is a paucity of information in the Niger Delta region on the distribution of Aedes mosquito vectors and molecular detection of the virus in infected mosquitoes. This study sampled Aedes mosquitoes around houses associated with farms from four communities (Otolokpo, Ute-Okpu, Umunede, and Ute Alohen) in Ika North-East Local Government Area of Delta State, Nigeria. Methods: various sampling methods were used in Aedes mosquito collection to test their efficacy in the survey. Mosquitoes in holding cages were killed by freezing and morphologically identified. A pool of 15 mosquitoes per Eppendorf tube was preserved in RNAi later for yellow fever virus screening. Two samples were molecularly screened for each location. Results: seven hundred and twenty-five (725) mosquitoes were obtained from the various traps. The mean abundance of the mosquitoes was highest in m-HLC (42.9) compared to the mosquitoes sampled using other techniques (p<0.0001). The mean abundance of mosquitoes was lowest in Center for Disease Control (CDC) light traps without attractant (0.29). No yellow fever virus strain was detected in all the mosquitoes sampled at the four locations. Conclusion: this study suggests that Aedes albopictus are the mosquitoes commonly biting around houses associated with farms. More so, yellow fever virus was not detected in the mosquitoes probably due to the mass vaccination exercise that was carried out the previous year in the study area. More studies are required using the m-HLC to determine the infection rate in this endemic area.


Asunto(s)
Aedes , Mosquitos Vectores , Fiebre Amarilla , Virus de la Fiebre Amarilla , Animales , Aedes/virología , Nigeria , Virus de la Fiebre Amarilla/aislamiento & purificación , Mosquitos Vectores/virología , Fiebre Amarilla/transmisión , Fiebre Amarilla/epidemiología , Fiebre Amarilla/virología , Humanos
2.
Sci Rep ; 14(1): 10842, 2024 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-38735993

RESUMEN

Yellow fever outbreaks are prevalent, particularly in endemic regions. Given the lack of an established treatment for this disease, significant attention has been directed toward managing this arbovirus. In response, we developed a multiepitope vaccine designed to elicit an immune response, utilizing advanced immunoinformatic and molecular modeling techniques. To achieve this, we predicted B- and T-cell epitopes using the sequences from all structural (E, prM, and C) and nonstructural proteins of 196 YFV strains. Through comprehensive analysis, we identified 10 cytotoxic T-lymphocyte (CTL) and 5T-helper (Th) epitopes that exhibited overlap with B-lymphocyte epitopes. These epitopes were further evaluated for their affinity to a wide range of human leukocyte antigen system alleles and were rigorously tested for antigenicity, immunogenicity, allergenicity, toxicity, and conservation. These epitopes were linked to an adjuvant ( ß -defensin) and to each other using ligands, resulting in a vaccine sequence with appropriate physicochemical properties. The 3D structure of this sequence was created, improved, and quality checked; then it was anchored to the Toll-like receptor. Molecular Dynamics and Quantum Mechanics/Molecular Mechanics simulations were employed to enhance the accuracy of docking calculations, with the QM portion of the simulations carried out utilizing the density functional theory formalism. Moreover, the inoculation model was able to provide an optimal codon sequence that was inserted into the pET-28a( +) vector for in silico cloning and could even stimulate highly relevant humoral and cellular immunological responses. Overall, these results suggest that the designed multi-epitope vaccine can serve as prophylaxis against the yellow fever virus.


Asunto(s)
Epítopos de Linfocito T , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Virus de la Fiebre Amarilla , Vacuna contra la Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/genética , Humanos , Fiebre Amarilla/prevención & control , Fiebre Amarilla/inmunología , Epítopos de Linfocito T/inmunología , Epítopos de Linfocito B/inmunología , Vacunología/métodos , Modelos Moleculares , Desarrollo de Vacunas , Simulación de Dinámica Molecular , Linfocitos T Citotóxicos/inmunología
3.
PLoS One ; 19(5): e0302496, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38709760

RESUMEN

Adult mosquitoes require regular sugar meals, including nectar, to survive in natural habitats. Both males and females locate potential sugar sources using sensory proteins called odorant receptors (ORs) activated by plant volatiles to orient toward flowers or honeydew. The yellow fever mosquito, Aedes aegypti (Linnaeus, 1762), possesses a large gene family of ORs, many of which are likely to detect floral odors. In this study, we have uncovered ligand-receptor pairings for a suite of Aedes aegypti ORs using a panel of environmentally relevant, plant-derived volatile chemicals and a heterologous expression system. Our results support the hypothesis that these odors mediate sensory responses to floral odors in the mosquito's central nervous system, thereby influencing appetitive or aversive behaviors. Further, these ORs are well conserved in other mosquitoes, suggesting they function similarly in diverse species. This information can be used to assess mosquito foraging behavior and develop novel control strategies, especially those that incorporate mosquito bait-and-kill technologies.


Asunto(s)
Aedes , Flores , Receptores Odorantes , Compuestos Orgánicos Volátiles , Animales , Aedes/fisiología , Aedes/metabolismo , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/análisis , Femenino , Masculino , Fiebre Amarilla/transmisión , Odorantes/análisis , Plantas/metabolismo , Plantas/química
4.
J Am Mosq Control Assoc ; 40(2): 112-116, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38697617

RESUMEN

Among all living beings, mosquitoes account for the highest number of human fatalities. Our study aimed to determine mosquito egg abundance fluctuation from 2015 to 2020, in order to observe which years had the highest mosquito vector densities and whether they coincided with yellow fever virus outbreaks in both human and nonhuman primates. The study area included Atlantic Forest fragments in the state of Rio de Janeiro. Studies from the Diptera Laboratory at FIOCRUZ were selected and compared along a timeline period of the field collections. The highest peak in egg abundance from the analyzed studies was observed from 2016 to 2017 and from 2015 to 2016. The lowest egg abundance was during the collection periods from 2018 to 2019 and 2019 to 2020. The species with the highest abundance throughout all the periods of the studies analyzed was Haemagogus leucocelaenus, representing 87% of all epidemiological species identified. The species with the lowest abundance was Hg. Janthinomys, representing only 1%. Monitoring the population of mosquitoes is imperative for disease surveillance, as the rise in specimens of various vector species directly impacts the occurrence of yellow fever cases in both nonhuman primates and human populations.


Asunto(s)
Culicidae , Brotes de Enfermedades , Bosques , Mosquitos Vectores , Fiebre Amarilla , Animales , Brasil/epidemiología , Fiebre Amarilla/epidemiología , Fiebre Amarilla/transmisión , Mosquitos Vectores/fisiología , Culicidae/fisiología , Humanos , Densidad de Población , Dinámica Poblacional , Virus de la Fiebre Amarilla
5.
PLoS Negl Trop Dis ; 18(5): e0012173, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38739650

RESUMEN

BACKGROUND: Yellow fever (YF), a mosquito-borne viral hemorrhagic fever, is endemic in Uganda and causes frequent outbreaks. A total of 1.6 million people were vaccinated during emergency mass immunization campaigns in 2011 and 2016. This study explored local perceptions of YF emergency mass immunization among vulnerable groups to inform future vaccination campaigns. METHODOLOGY: In this qualitative study, we conducted 43 semi-structured interviews, 4 focus group discussions, and 10 expert interviews with 76 participants. Data were collected in six affected districts with emergency mass vaccination. We included vulnerable groups (people ≥ 65 years and pregnant women) who are typically excluded from YF vaccination except during mass immunization. Data analysis was conducted using grounded theory. Inductive coding was utilized, progressing through open, axial, and selective coding. PRINCIPAL FINDINGS: Participants relied on community sources for information about the YF mass vaccination. Information was disseminated door-to-door, in community spaces, during religious gatherings, and on the radio. However, most respondents had no knowledge of the vaccine, and it was unclear to them whether a booster dose was required. In addition, the simultaneous presidential election during the mass vaccination campaign led to suspicion and resistance to vaccination. The lack of reliable and trustworthy information and the politicization of vaccination campaigns reinforced mistrust of YF vaccines. CONCLUSIONS/SIGNIFICANCE: People in remote areas affected by YF outbreaks rely on community sources of information. We therefore recommend improving health education, communication, and engagement through respected and trusted community members. Vaccination campaigns can never be seen as detached from political systems and power relations.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Vacunación Masiva , Investigación Cualitativa , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Humanos , Uganda/epidemiología , Femenino , Fiebre Amarilla/prevención & control , Fiebre Amarilla/epidemiología , Masculino , Vacuna contra la Fiebre Amarilla/administración & dosificación , Vacunación Masiva/psicología , Anciano , Persona de Mediana Edad , Poblaciones Vulnerables , Adulto , Embarazo , Brotes de Enfermedades/prevención & control , Grupos Focales
6.
Artículo en Inglés | MEDLINE | ID: mdl-38791823

RESUMEN

In the Americas, wild yellow fever (WYF) is an infectious disease that is highly lethal for some non-human primate species and non-vaccinated people. Specifically, in the Brazilian Atlantic Forest, Haemagogus leucocelaenus and Haemagogus janthinomys mosquitoes act as the major vectors. Despite transmission risk being related to vector densities, little is known about how landscape structure affects vector abundance and movement. To fill these gaps, we used vector abundance data and a model-selection approach to assess how landscape structure affects vector abundance, aiming to identify connecting elements for virus dispersion in the state of São Paulo, Brazil. Our findings show that Hg. leucocelaenus and Hg. janthinomys abundances, in highly degraded and fragmented landscapes, are mainly affected by increases in forest cover at scales of 2.0 and 2.5 km, respectively. Fragmented landscapes provide ecological corridors for vector dispersion, which, along with high vector abundance, promotes the creation of risk areas for WYF virus spread, especially along the border with Minas Gerais state, the upper edges of the Serra do Mar, in the Serra da Cantareira, and in areas of the metropolitan regions of São Paulo and Campinas.


Asunto(s)
Mosquitos Vectores , Fiebre Amarilla , Brasil , Animales , Fiebre Amarilla/transmisión , Mosquitos Vectores/virología , Ecosistema , Clima Tropical , Virus de la Fiebre Amarilla , Densidad de Población , Culicidae/virología , Culicidae/fisiología
7.
Int J Biol Macromol ; 269(Pt 2): 132169, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38723801

RESUMEN

In our study, we developed a point of care electrochemical biosensing platform based on the functionalized cysteine-positioned gold electrode to diagnose yellow fever disease from human plasma samples. The developed platform underwent characterization through diverse methods encompassing cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and density-functional theory. The capacitive interaction between yellow fever virus non-structural antigen and antibody gave a cathodic signal at approximately -260 mV, and increased in proportion to the amount of non-structural antibody. The created electrochemical biosensor has an ability to detect 96 ag/mL of the yellow fever non-structural antibody with an extensive analytical range varied from 0.1 fg/mL to 1 µg/mL. The interference effects of various substances that could be found in human plasma, and the performance of the method were examined from the point of recovery and relative standard deviation for human plasma samples; hereby, the results confirmed the unprecedented selectivity and accuracy of the proposed method.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Proteínas no Estructurales Virales , Fiebre Amarilla , Humanos , Técnicas Biosensibles/métodos , Fiebre Amarilla/diagnóstico , Fiebre Amarilla/sangre , Fiebre Amarilla/inmunología , Fiebre Amarilla/virología , Proteínas no Estructurales Virales/inmunología , Proteínas no Estructurales Virales/sangre , Técnicas Electroquímicas/métodos , Sistemas de Atención de Punto , Virus de la Fiebre Amarilla/inmunología , Teoría Funcional de la Densidad , Electrodos , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Oro/química
8.
Sci Rep ; 14(1): 7709, 2024 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-38565882

RESUMEN

The present study aimed at evaluating the YF-specific neutralizing antibody profile besides a multiparametric analysis of phenotypic/functional features of cell-mediated response elicited by the 1/5 fractional dose of 17DD-YF vaccine, administered as a single subcutaneous injection. The immunological parameters of each volunteer was monitored at two time points, referred as: before (Day 0) [Non-Vaccinated, NV(D0)] and after vaccination (Day 30-45) [Primary Vaccinees, PV(D30-45)]. Data demonstrated high levels of neutralizing antibodies for PV(D30-45) leading to a seropositivity rate of 93%. A broad increase of systemic soluble mediators with a mixed profile was also observed for PV(D30-45), with IFN-γ and TNF-α presenting the highest baseline fold changes. Integrative network mapping of soluble mediators showed increased correlation numbers in PV(D30-45) as compared to NV(D0) (532vs398). Moreover, PV(D30-45) exhibited increased levels of Terminal Effector (CD45RA+CCR7-) CD4+ and CD8+ T-cells and Non-Classical memory B-cells (IgD+CD27+). Dimensionality reduction of Mass Cytometry data further support these findings. A polyfunctional cytokine profile (TNF-α/IFN-γ/IL-10/IL-17/IL-2) of T and B-cells was observed upon in vitro antigen recall. Mapping and kinetics timeline of soluble mediator signatures for PV(D30-45) further confirmed the polyfunctional profile upon long-term in vitro culture, mediated by increased levels of IFN-γ and TNF-α along with decreased production of IL-10. These findings suggest novel insights of correlates of protection elicited by the 1/5 fractional dose of 17DD-YF vaccine.


Asunto(s)
Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Humanos , Adulto , Anticuerpos Neutralizantes , Interleucina-10 , Anticuerpos Antivirales , Factor de Necrosis Tumoral alfa , Linfocitos T CD8-positivos , Vacunación
9.
Eur J Immunol ; 54(5): e2250133, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38571392

RESUMEN

Live-attenuated yellow fever vaccine (YF17D) was developed in the 1930s as the first ever empirically derived human vaccine. Ninety years later, it is still a benchmark for vaccines made today. YF17D triggers a particularly broad and polyfunctional response engaging multiple arms of innate, humoral and cellular immunity. This unique immunogenicity translates into an extraordinary vaccine efficacy and outstanding longevity of protection, possibly by single-dose immunization. More recently, progress in molecular virology and synthetic biology allowed engineering of YF17D as a powerful vector and promising platform for the development of novel recombinant live vaccines, including two licensed vaccines against Japanese encephalitis and dengue, even in paediatric use. Likewise, numerous chimeric and transgenic preclinical candidates have been described. These include prophylactic vaccines against emerging viral infections (e.g. Lassa, Zika and SARS-CoV-2) and parasitic diseases (e.g. malaria), as well as therapeutic applications targeting persistent infections (e.g. HIV and chronic hepatitis), and cancer. Efforts to overcome historical safety concerns and manufacturing challenges are ongoing and pave the way for wider use of YF17D-based vaccines. In this review, we summarize recent insights regarding YF17D as vaccine platform, and how YF17D-based vaccines may complement as well as differentiate from other emerging modalities in response to unmet medical needs and for pandemic preparedness.


Asunto(s)
Vacunas Atenuadas , Vacuna contra la Fiebre Amarilla , Virus de la Fiebre Amarilla , Humanos , Vacuna contra la Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/inmunología , Vacunas Atenuadas/inmunología , Animales , Fiebre Amarilla/prevención & control , Fiebre Amarilla/inmunología , Vacunación/métodos
10.
J Virol ; 98(5): e0151623, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38567951

RESUMEN

The non-human primate (NHP) model (specifically rhesus and cynomolgus macaques) has facilitated our understanding of the pathogenic mechanisms of yellow fever (YF) disease and allowed the evaluation of the safety and efficacy of YF-17D vaccines. However, the accuracy of this model in mimicking vaccine-induced immunity in humans remains to be fully determined. We used a systems biology approach to compare hematological, biochemical, transcriptomic, and innate and antibody-mediated immune responses in cynomolgus macaques and human participants following YF-17D vaccination. Immune response progression in cynomolgus macaques followed a similar course as in adult humans but with a slightly earlier onset. Yellow fever virus neutralizing antibody responses occurred earlier in cynomolgus macaques [by Day 7[(D7)], but titers > 10 were reached in both species by D14 post-vaccination and were not significantly different by D28 [plaque reduction neutralization assay (PRNT)50 titers 3.6 Log vs 3.5 Log in cynomolgus macaques and human participants, respectively; P = 0.821]. Changes in neutrophils, NK cells, monocytes, and T- and B-cell frequencies were higher in cynomolgus macaques and persisted for 4 weeks versus less than 2 weeks in humans. Low levels of systemic inflammatory cytokines (IL-1RA, IL-8, MIP-1α, IP-10, MCP-1, or VEGF) were detected in either or both species but with no or only slight changes versus baseline. Similar changes in gene expression profiles were elicited in both species. These included enriched and up-regulated type I IFN-associated viral sensing, antiviral innate response, and dendritic cell activation pathways D3-D7 post-vaccination in both species. Hematological and blood biochemical parameters remained relatively unchanged versus baseline in both species. Low-level YF-17D viremia (RNAemia) was transiently detected in some cynomolgus macaques [28% (5/18)] but generally absent in humans [except one participant (5%; 1/20)].IMPORTANCECynomolgus macaques were confirmed as a valid surrogate model for replicating YF-17D vaccine-induced responses in humans and suggest a key role for type I IFN.


Asunto(s)
Macaca fascicularis , Modelos Animales , Vacuna contra la Fiebre Amarilla , Animales , Femenino , Humanos , Masculino , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Inmunidad Innata , Biología de Sistemas/métodos , Vacunación , Fiebre Amarilla/prevención & control , Fiebre Amarilla/inmunología , Fiebre Amarilla/virología , Vacuna contra la Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/inmunología
11.
Biologicals ; 86: 101765, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38593685

RESUMEN

Yellow fever (YF) is one of the most acute viral hemorrhagic diseases of the 18th and 19th centuries, which continues to cause severe morbidity and mortality in Africa. After 21 years of no reported cases of yellow fever in Nigeria, till 2017 where a case was confirmed in Kwara State, also in November 2018,WHO was informed of a cluster of suspected yellow fever cases and deaths in Edo state, Nigeria. The study was among all age group attending health centres in Benin City, Edo state. A total of 280 blood samples were collected from consented febrile patients and were screened for antibodies to Zika virus using rapid diagnostic test (RDT) kits. Blood samples positive to Zika virus (IgM/IgG RDT), were subjected to molecular characterization. Using the flavividae family primers, six (6) samples where confirmed positive by Hemi-nested reverse transcription PCR (hnRT-PCR) sequencing. Nucleotide sequence blast revealed the sequenceswere similar to Yellow fever virus strains. Phylogenetic analysis revealed that the yellow fever virus sequences are closely related to the African strains. Despite the safe and effective yellow fever vaccine, yellow fever virus is seen to be in circulation, hence the need for continues mass vaccination.


Asunto(s)
Filogenia , Fiebre Amarilla , Virus de la Fiebre Amarilla , Humanos , Nigeria/epidemiología , Virus de la Fiebre Amarilla/genética , Virus de la Fiebre Amarilla/inmunología , Fiebre Amarilla/epidemiología , Fiebre Amarilla/virología , Fiebre Amarilla/sangre , Adulto , Femenino , Masculino , Adolescente , Persona de Mediana Edad , Niño , Preescolar , Adulto Joven , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Lactante , Virus Zika/genética , Virus Zika/inmunología , Virus Zika/aislamiento & purificación
14.
Lancet Glob Health ; 12(4): e563-e571, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38485425

RESUMEN

BACKGROUND: There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered. METHODS: For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up. FINDINGS: We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]). INTERPRETATION: Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption. FUNDING: The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation. TRANSLATIONS: For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.


Asunto(s)
COVID-19 , Hepatitis B , Sarampión , Meningitis , Infecciones por Papillomavirus , Vacunas contra Papillomavirus , Rubéola (Sarampión Alemán) , Enfermedades Prevenibles por Vacunación , Fiebre Amarilla , Humanos , Infecciones por Papillomavirus/prevención & control , Pandemias , COVID-19/epidemiología , COVID-19/prevención & control , Vacunación , Inmunización , Hepatitis B/tratamiento farmacológico
15.
J Travel Med ; 31(3)2024 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-38438165

RESUMEN

BACKGROUND: Vaccination plays a critical role in mitigating the burden associated with yellow fever (YF). However, there is a lack of comprehensive evidence on the humoral response to primary vaccination in the paediatric population, with several questions debated, including the response when the vaccine is administered at early ages, the effect of co-administration with other vaccines, the duration of immunity and the use of fractional doses, among others. This study summarizes the existing evidence regarding the humoral response to primary YF vaccination in infants and children. METHODS: Studies on the humoral response to primary YF vaccination in children aged 12 years or younger were reviewed. The humoral vaccine response rate (VRR), i.e. the proportion of children who tested positive for vaccine-induced YF-specific neutralizing antibodies, was pooled through random-effects meta-analysis and categorized based on the time elapsed since vaccination. Subgroup, meta-regression and sensitivity analyses were performed. RESULTS: A total of 33 articles met the inclusion criteria, with all but one conducted in countries where YF is endemic. A total of 14 028 infants and children entered this systematic review. Within three months following vaccination, the pooled VRR was 91.9% (95% CI 89.8-93.9). A lower VRR was observed with the 17DD vaccine at the meta-regression analysis. No significant differences in immunogenicity outcomes were observed based on age, administration route, co-administration with other vaccines, or fractional dosing. Results also indicate a decline in VRR over time. CONCLUSIONS: Primary YF vaccination effectively provides humoral immunity in paediatric population. However, humoral response declines over time, and this decline is observable after the first 18 months following vaccination. A differential response according to the vaccine substrain was also observed. This research has valuable implications for stimulating further research on the primary YF vaccination in infants and children, as well as for informing future policies.


Asunto(s)
Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Niño , Lactante , Humanos , Fiebre Amarilla/prevención & control , Anticuerpos Neutralizantes , Vacunación/métodos , Inmunidad Humoral , Anticuerpos Antivirales
16.
Microbiol Spectr ; 12(5): e0370323, 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38511952

RESUMEN

Between 2016 and 2018, Brazil experienced major sylvatic yellow fever (YF) outbreaks that caused hundreds of casualties, with Minas Gerais (MG) being the most affected state. These outbreaks provided a unique opportunity to assess the immune response triggered by the wild-type (WT) yellow fever virus (YFV) in humans. The plaque reduction neutralization test (PRNT) is currently the standard method to assess the humoral immune response to YFV by measuring neutralizing antibodies (nAbs). The present study aimed to evaluate the humoral immune response of patients from the 2017-2018 sylvatic YF outbreak in MG with different disease outcomes by using PRNTs with a WT YFV strain, isolated from the 2017-2018 outbreak, and a vaccine YFV strain. Samples from naturally infected YF patients were tested, in comparison with healthy vaccinees. Results showed that both groups presented different levels of nAb against the WT and vaccine strains, and the levels of neutralization against the strains varied homotypically and heterotypically. Results based on the geometric mean titers (GMTs) suggest that the humoral immune response after a natural infection of YFV can reach higher levels than that induced by vaccination (GMT of patients against WT YFV compared to GMT of vaccinees, P < 0.0001). These findings suggest that the humoral immune responses triggered by the vaccine and WT strains of YFV are different, possibly due to genetic and antigenic differences between these viruses. Therefore, current means of assessing the immune response in naturally infected YF individuals and immunological surveillance methods in areas with intense viral circulation may need to be updated.IMPORTANCEYellow fever is a deadly febrile disease caused by the YFV. Despite the existence of effective vaccines, this disease still represents a public health concern worldwide. Much is known about the immune response against the vaccine strains of the YFV, but recent studies have shown that it differs from that induced by WT strains. The extent of this difference and the mechanisms behind it are still unclear. Thus, studies aimed to better understand the immune response against this virus are relevant and necessary. The present study evaluated levels of neutralizing antibodies of yellow fever patients from recent outbreaks in Brazil, in comparison with healthy vaccinees, using plaque reduction neutralization tests with WT and vaccine YFV strains. Results showed that the humoral immune response in naturally infected patients was higher than that induced by vaccination, thus providing new insights into the immune response triggered against these viruses.


Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Antivirales , Brotes de Enfermedades , Inmunidad Humoral , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Virus de la Fiebre Amarilla , Fiebre Amarilla/inmunología , Fiebre Amarilla/epidemiología , Fiebre Amarilla/virología , Humanos , Brasil/epidemiología , Virus de la Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/genética , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Masculino , Vacuna contra la Fiebre Amarilla/inmunología , Femenino , Adulto , Persona de Mediana Edad , Vacunación , Pruebas de Neutralización , Adulto Joven , Anciano , Adolescente
17.
Int J Infect Dis ; 143: 107017, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38521450

RESUMEN

Yellow fever (YF) is a potentially lethal viral hemorrhagic fever that can be prevented with the 17D live attenuated YF vaccine. However, this vaccination can cause severe adverse reactions including vaccine-associated YF. Here, we describe the case of a 32-year-old female who was permanently immunosuppressed with an anti-CD20 antibody due to multiple sclerosis. Following YF vaccination, the patient developed a variety of symptoms such as febrile temperatures, muscle and joint pain, headaches, and dysuria. A vaccine-associated YF with viremia was diagnosed. To avoid a potentially severe course of the disease, sofosbuvir was used as antiviral treatment followed by the resolution of symptoms and serological response. As travelers with chronic diseases and immunosuppression will increasingly engage in long distance travel, this case demonstrates the importance of assessing patient history prior to the administration of live vaccines and points towards a possible therapeutic approach in those suffering from vaccine-associated YF.


Asunto(s)
Antivirales , Huésped Inmunocomprometido , Sofosbuvir , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Adulto , Femenino , Humanos , Antivirales/uso terapéutico , Antivirales/efectos adversos , Rituximab/efectos adversos , Rituximab/uso terapéutico , Sofosbuvir/uso terapéutico , Sofosbuvir/efectos adversos , Fiebre Amarilla/inmunología , Vacuna contra la Fiebre Amarilla/efectos adversos , Vacuna contra la Fiebre Amarilla/inmunología , Antígenos CD20/inmunología , Antígenos CD20/uso terapéutico , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/terapia
18.
Aust J Rural Health ; 32(3): 455-461, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38506501

RESUMEN

INTRODUCTION: Yellow fever is caused by an RNA flavivirus. Immunisation in conjunction with vector control is at the forefront of yellow fever control and elimination. OBJECTIVE: This narrative review describes the impact and importance of yellow fever vaccinations for northern Australian health practitioners. DESIGN: Selected key policies, studies and medical guidelines are reviewed and presented. FINDING: Large yellow fever outbreaks, associated with vector spread, have occurred in the last decade in Africa and South America, increasing the risk of international spread of the virus. Mobile populations, like travellers or migrant workers, continue to be at risk of yellow fever. Quality assurance, including yellow fever centre accreditation and initiatives to decrease fraudulent yellow fever vaccination documentation, has evolved in the past few years. Fractional dosing of yellow fever vaccines has been shown to provide protection for 1 year in outbreak scenarios, but further studies are needed. DISCUSSION: Although Australia is yellow fever-free, the disease could be introduced by viraemic persons as a competent Aedes mosquito vector is present in northern Australia. In addition to surveillance and vector control, health education and yellow fever vaccination remain the best lines of defence. In the event of an outbreak, a response via fractional dosing could prove to be effective in controlling the virus. CONCLUSION: Health care providers in northern Australia should be aware of the risks of yellow fever and its introduction to northern Australia and be able to discuss vaccination status with their clients when needed.


Asunto(s)
Brotes de Enfermedades , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Humanos , Fiebre Amarilla/prevención & control , Fiebre Amarilla/epidemiología , Vacuna contra la Fiebre Amarilla/administración & dosificación , Australia/epidemiología , Brotes de Enfermedades/prevención & control , Animales
19.
Vaccine ; 42(11): 2729-2732, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38514353

RESUMEN

Studies on yellow fever vaccine (YF) in chronic kidney disease (CKD) patients are scarce. This cross-sectional study aimed to evaluate YF neutralizing antibody seroprevalence and titers in previously vaccinated adults with CKD, on dialysis (D-CKD) or not (ND-CKD), compared to healthy persons. The micro Plaque Reduction Neutralization-Horseradish Peroxidase (µPRN-HP) test was used. Antibody titers were expressed as the reciprocal of the highest dilution that neutralized the challenge virus by 50 % (µPRN50). Seropositivity cut-off was set at ≥ 1:100. We included 153 participants: 46 ND-CKD, 50 D-CKD and 57 healthy adults. Median ages were 58.3, 55 and 52.2 years, respectively. Median time since YF vaccination was 22.3, 18.5 and 48.3 months respectively. There were no statistically significant differences in YF seroprevalence and neutralizing antibodies titers among groups: 100 % of ND-CKD; 96 % of D-CKD and 100 % of healthy participants were seropositive. Geometric mean titers (GMT) were 818.5, 683.0 and 665.5, respectively (p = 0.289).


Asunto(s)
Insuficiencia Renal Crónica , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Adulto , Humanos , Fiebre Amarilla/prevención & control , Anticuerpos Neutralizantes , Estudios Transversales , Estudios Seroepidemiológicos , Anticuerpos Antivirales , Virus de la Fiebre Amarilla , Vacunación , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/terapia
20.
Trials ; 25(1): 216, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38532475

RESUMEN

RATIONALE: The effectiveness of immunisation with pneumococcal conjugate vaccine (PCV) has been demonstrated in many countries. However, the global impact of PCV is limited by its cost, which has prevented its introduction in some countries. Reducing the cost of PCV programmes will facilitate further vaccine introductions and improve the sustainability of PCV in low-income countries when they transition from subsidised vaccine supply. We are conducting a large, population-level, cluster-randomised field trial (PVS) of an alternative reduced-dose schedule of PCV compared to the standard schedule. We are also conducting a nested sub-study at the individual level to investigate the immunogenicity of the two schedules and their effects on pneumococcal carriage acquisition (PVS-AcqImm). METHODS AND DESIGN: PVS-AcqImm is a prospective, cluster-randomised trial of an alternative schedule of one dose of PCV scheduled at age 6 weeks with a booster dose at age 9 months compared to the standard of three primary doses scheduled at 6, 10, and 14 weeks of age. Sub-groups within the alternative schedule group receive yellow fever vaccine separately or co-administered with PCV at 9 months of age. The primary endpoints are (a) concentrations of vaccine-type anti-pneumococcal IgG at 18 months of age, (b) proportions with yellow fever neutralising antibody titre ≥ 1:8 4 weeks after separate or co-administration of PCV and yellow fever vaccines, and (c) rate of nasopharyngeal vaccine-type pneumococcal acquisition from 10-14 months of age. Participants and field staff are not masked to group allocation while measurement of the laboratory endpoints is masked. Approximately equal numbers of participants are resident in each of 28 randomly allocated geographic clusters (14 clusters in each group); 784 enrolled for acquisition measurements and 336 for immunogenicity measurements. PURPOSE: This statistical analysis plan (SAP) describes the PVS-AcqImm cohort and follow-up criteria to be used in different analyses. The SAP defines the endpoints and describes how adherence to the interventions will be presented. We describe the approach to analyses and how we will account for the effect of clustering. Defining the SAP prior to the conduct of analysis will avoid bias in analyses that may arise from prior knowledge of trial findings. TRIAL REGISTRATION: ISRCTN, ISRCTN7282161328. Registered on 28 November 2019. https://www.isrctn.com/ISRCTN72821613 . PROTOCOL: MRCG SCC number 1670, LSHTM Ref 17683. Current protocol version: 6.0, 24 May 2021. Version: 1.0 (5 April 2023); SAP revisions-none.


Asunto(s)
Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Humanos , Lactante , Esquemas de Inmunización , Vacunas Neumococicas , Estudios Prospectivos , Streptococcus pneumoniae , Vacunación/métodos , Vacunas Conjugadas
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