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Minimal immune response to booster vaccination against Yellow Fever associated with pre-existing antibodies.

Ever since its development in the 1930's, the live-attenuated Yellow Fever virus vaccine YF-17D has been highly effective. Despite the increasing knowledge on the immune biology of the YF-17D vaccine, most studies have focused only on a few types of immune cells and pathways or mainly on the primary adaptive immune response to YF-17D vaccination. Here, we examined humoral, innate and adaptive cellular responses in a longitudinal YF-17D vaccination study in Switzerland, comparing both primary and booster vaccination. In contrast to the strong innate and adaptive immune response to the primary v…

Safety and immunogenicity of 17DD attenuated yellow fever vaccine in howler monkeys (Alouatta spp.).

BACKGROUND: Alouatta spp. are highly susceptible to yellow fever (YF) infection and develop an often fatal disease. The threat posed by an outbreak started in 2016 leads us to investigate vaccination as a potential tool in preventing YF in non-human primates (NHP). METHODS: Susceptible howler monkeys were immunized with three different concentrations of the human Brazilian commercial YF17DD vaccine. Post-vaccination viremia/RNAemia, immunogenicity, and safety were characterized. RESULTS: The vaccine did not produce YF clinical manifestations in any of the NHPs. After immunization, all animal…

Recent sylvatic yellow fever virus transmission in Brazil: the news from an old disease.

Yellow fever (YF) is an acute viral disease, affecting humans and non-human primates (NHP), caused by the yellow fever virus (YFV). Despite the existence of a safe vaccine, YF continues to cause morbidity and mortality in thousands of people in Africa and South America. Since 2016, massive YF outbreaks have taken place in Brazil, reaching YF-free zones, causing thousands of deaths of humans and NHP. Here we reviewed the main epidemiological aspects, new clinical findings in humans, and issues regarding YFV infection in vectors and NHP in Brazil. The 2016-2019 YF epidemics have been considered …

Structure of the yellow fever NS5 protein reveals conserved drug targets shared among flaviviruses.

Yellow fever virus (YFV) is responsible for devastating outbreaks of Yellow fever (YF) in humans and is associated with high mortality rates. Recent large epidemics and epizootics and exponential increases in the numbers of YF cases in humans and non-human primates highlight the increasing threat YFV poses, despite the availability of an effective YFV vaccine. YFV is the first human virus discovered, but the structures of several of the viral proteins remain poorly understood. Here we report the structure of the full-length NS5 protein, a key enzyme for the replication of flaviviruses that con…

Mosquito and primate ecology predict human risk of yellow fever virus spillover in Brazil.

Many (re)emerging infectious diseases in humans arise from pathogen spillover from wildlife or livestock, and accurately predicting pathogen spillover is an important public health goal. In the Americas, yellow fever in humans primarily occurs following spillover from non-human primates via mosquitoes. Predicting yellow fever spillover can improve public health responses through vector control and mass vaccination. Here, we develop and test a mechanistic model of pathogen spillover to predict human risk for yellow fever in Brazil. This environmental risk model, based on the ecology of mosquito…

Yellow fever virus: historical and current issues regarding recent epidemics and vaccination in Brazil.

Yellow fever has been recently described in nonurban areas of Brazil despite 80 years of commercial vaccine use. Although the disease does not spread fear in the general population as it did in the past, yellow fever virus continues to cause many cases of severe disease. Persistence of the virus in the host is a new mechanism to be considered in the pathology of the disease. Immunization with a fractional dose of vaccine during emergency situations needs to be evaluated for antibody duration, and new and improved vaccines should be considered.

Community knowledge, attitudes and practices on Yellow fever in South Omo area, Southern Ethiopia.

BACKGROUND: Yellow fever (Yf) outbreak was recently reported in South Omo of Southern Ethiopia. This area was also highly affected by Yf outbreak in the 1960s. However, there is no reliable information on the level of community knowledge attitudes and practices about the disease in the area. The objective of the current study was to assess level of community knowledge, attitudes and practices about Yf. METHODS: Between March and May 2017, a community-based cross-sectional survey was conducted in two districts of the South Omo area. During the survey, 612 randomly selected adults were intervie…

[Anti-NMDAR encephalitis as a serious adverse event probably related to yellow fever vaccination].

We present a case of a 17-year-old female with anti-NMDAR encephalitis probably associated with vaccination against yellow fever. Her symptoms occurred 27 days after vaccination against yellow fever. Anti-NMDAR encephalitis manifested as acute psychosis, memory loss and catatonia following fever with complex partial epileptic seizures. Interictal electroencephalogram showed slow-wave delta background activity with "delta brushes". The diagnosis was confirmed by NMDAR antibody positivity in serum and cerebrospinal fluid. Since ovarian teratoma, as the most common cause of anti-NMDAR encephaliti…

Screening test for neutralizing antibodies against yellow fever virus, based on a flavivirus pseudotype.

Given the possibility of yellow fever virus reintroduction in epidemiologically receptive geographic areas, the risk of vaccine supply disruption is a serious issue. New strategies to reduce the doses of injected vaccines should be evaluated very carefully in terms of immunogenicity. The plaque reduction test for the determination of neutralizing antibodies (PRNT) is particularly time-consuming and requires the use of a confinement laboratory. We have developed a new test based on the use of a non-infectious pseudovirus (WN/YF17D). The presence of a reporter gene allows sensitive determination…

Строение протеина формирует иммунодоминацию в реакции CD4 T на прививку от желтой лихорадки.

Вакцина с улучшенной желтой лихорадкой (YF) является высокоэффективной вакциной человека и вызывает долгосрочную защиту от антител, направленных против вирусного белка Е. Формирование таких антител требует помощи CD4 T клеток, которые распознают пептиды, полученные из белков в частицах вируса, интернализированных и обработанных конкретными клетками В. Реакция на CD4 T ассистентной клетки ограничена небольшим количеством иммунодоминантных эпитопов, но механизмы их отбора в значительной степени неизвестны. Здесь мы сообщаем, что реакция CD4 T, вызванная вакциной YF-17D, сфокусирована на горячих

Совпадение в аннотации оригинала
The live attenuated yellow fever (YF) vaccine is a highly effective human vaccine and induces long-term protective neutralizing antibodies directed against the viral envelope protein E. The generation of such antibodies requires the help of CD4 T cells which recognize peptides derived from proteins in virus particles internalized and processed by E-specific …

Lessons Learned from Emergency Response Vaccination Efforts for Cholera, Typhoid, Yellow Fever, and Ebola.

Countries must be prepared to respond to public health threats associated with emergencies, such as natural disasters, sociopolitical confli … on in collaboration with global partners to support emergency vaccination against cholera, typhoid, yellow fever, and Ebola, diseases for which a new vaccine or vaccine formulation has played a major role in response. Lessons learned will help countries prepare for future emergencies. Integration of vaccination with emergency response augments global health se …

First case of yellow fever vaccine-associated viscerotropic disease (YEL-AVD) in Hong Kong.

Yellow fever is an important and potentially fatal infection in tropical regions of Africa, South America, eastern Panama in Central America and Trinidad in the Caribbean. Yellow fever vaccination is not only crucial to reduce the disease risk and mortality in individuals travelling to these areas, but also an important public health measure to prevent the spread of the disease. Despite generally considered as a safe vaccine, yellow fever vaccine can rarely be associated with severe adverse reactions including yellow fever vaccine-associated viscerotropic disease (YEL-AVD). Here, we report the…

Multicolored silver nanoparticles for multiplexed disease diagnostics: distinguishing dengue, yellow fever, and Ebola viruses.

Rapid point-of-care (POC) diagnostic devices are needed for field-forward screening of severe acute systemic febrile illnesses. Multiplexed rapid lateral flow diagnostics have the potential to distinguish among multiple pathogens, thereby facilitating diagnosis and improving patient care. Here, we present a platform for multiplexed pathogen detection using multi-colored silver nanoplates. This design requires no external excitation source and permits multiplexed analysis in a single channel, facilitating integration and manufacturing.

Fluid absorption in the isolated midgut of adult female yellow fever mosquitoes (Aedes aegypti).

The transepithelial voltage (Vte) and the volume of isolated posterior midguts of adult female yellow fever mosquitoes (Aedes aegypti) were monitored. In all experiments, the initial Vte after filling the midgut was lumen negative, but subsequently became lumen positive at a rate of approximately 1 mV min(-1). Simultaneously, the midgut volume decreased, indicating spontaneous fluid absorption. When the midguts were filled and bathed with mosquito saline, the average rate of fluid absorption was 36.5±3.0 nl min(-1) (N=4, ±s.e.m.). In the presence of theophylline (10 mmol l(-1)), Vte reached si…

Yellow Fever Vaccine Booster Doses: Recommendations of the Advisory Committee on Immunization Practices, 2015.

On February 26, 2015, the Advisory Committee on Immunization Practices (ACIP) voted that a single primary dose of yellow fever vaccine provides long-lasting protection and is adequate for most travelers. ACIP also approved recommendations for at-risk laboratory personnel and certain travelers to receive additional doses of yellow fever vaccine (Box). The ACIP Japanese Encephalitis and Yellow Fever Vaccines Workgroup evaluated published and unpublished data on yellow fever vaccine immunogenicity and safety. The evidence for benefits and risks associated with yellow fever vaccine booster doses w…

Сооружение подгеномных репликонов желтой лихорадки с помощью метода гомологической рекомбинации дрожжей.

Репликон РНК, полученный из генома Флавивируса, является ценным инструментом для изучения вирусного репликации независимо от вирионной сборки и созревания, не говоря уже о большом потенциале для гетерологического генного выражения. В этом исследовании мы описали создание субгеномных репликонов вируса желтой лихорадки с помощью метода рекомбинации на дрожжевой основе. Плазмид с жёлтой лихорадкой 17D репликон штамма (pBSC-repYFV-17D), который ранее характеризовался, был обработан гетерологичным выражением генов зеленого флуоресцентного белка (repYFV-17D-GFP) и светлячка люциферазы (repYFV-17D-Lu

Совпадение в аннотации оригинала
RNA replicon derived from Flavivirus genome is a valuable tool for studying viral replication independent of virion assembly and maturation, besides being a great potential for heterologous gene expression. In this study we described the construction of subgenomic replicons of yellow fever virus by yeast-based homologous recombination technique. The plasmid …

[Assessment of vaccination coverage among travelers to areas where yellow fever is endemic (Senegal)].

This prospective survey, conducted at the Dakar airport from August 18, 2011, to May 8, 2012, asked a sample of travelers living in France and returning there after a stay in Senegal to complete a questionnaire. The aim of the study was to assess the determinants of vaccination coverage against yellow fever. The study included 10 298 travelers, with a median age of 48 years (interquartile range: 27-58); 52% were tourists, and 22% were traveling for business purposes. The measured level of anti-yellow fever vaccination coverage was 39.3%. Vaccination coverage was influenced by the travelers' le…

Development of a reverse transcription polymerase chain reaction method for yellow fever virus detection.

INTRODUCTION: Yellow fever is considered a re-emerging disease and is endemic in tropical regions of Africa and South America. At present, there are no standardized or commercialized kits available for yellow fever virus detection. Therefore, diagnosis must be made by time-consuming routine techniques, and sometimes, the virus or its proteins are not detected. Furthermore, co-circulation with other flaviviruses, including dengue virus, increases the difficulty of diagnosis. OBJECTIVE: To develop a specific reverse transcriptase-polymerase chain reaction (RT-PCR) and nested PCR-based assay to …