Reações de hipersensibilidade a vacinas / Hypersensitivity reactions to vaccines

O desenvolvimento e a ampliação do uso das vacinas durante décadas contribuíram para o controle e erradicação de doenças infecciosas, causando um grande impacto na saúde pública no mundo. A análise de segurança das vacinas percorre criteriosos processos e fases dos estudos clínicos, um dos pilares essenciais para aprovação regulatória e utilização do produto na população. O evento supostamente atribuído à vacinação e imunização (ESAVI), terminologia atual, é definido como qualquer ocorrência médica indesejada após a vacinação que possui, ou não, uma relação causal com o uso de uma vacina ou outro imunobiológico. Cabe ressaltar que eventos adversos mais raros ou inesperados, incluindo os eventos de hipersensibilidade, poderão ocorrer na fase pós-comercialização, quando as vacinas são aplicadas em milhões de pessoas. Neste artigo, serão discutidos os principais aspectos relacionados aos eventos adversos de hipersensibilidade pós-vacinais de interesse do especialista, e os desafios frente ao reconhecimento do agente causal e conduta a ser adotada. Além disso, serão revisados os potenciais alérgenos presentes nas vacinas de uso rotineiro para auxiliar o profissional de saúde na identificação de pacientes com potencial de risco de ESAVI por tais componentes. A atualização do conhecimento acerca da segurança e dos benefícios das vacinas pelos profissionais de saúde, sobretudo em populações especiais, contribui para condutas em imunização mais apropriadas, reduzindo o risco de exposição a um possível alérgeno em pessoas comprovadamente alérgicas às vacinas ou a alguns dos seus componentes, além de evitar contraindicações desnecessárias em eventos coincidentes ou não graves.

The expansion of vaccine use and development in recent decades has contributed to the control and eradication of infectious diseases, causing a major impact on public health worldwide. Vaccine safety analysis, which involves careful processes and clinical study, is one of the essential pillars of regulatory approval and use in the population. In current terminology, events supposedly attributable to vaccination and immunization (ESAVI) are defined as any unwanted medical occurrence after vaccination that may or may not have a causal relationship with vaccines or other immunobiologicals. It is noteworthy that rare or unexpected adverse events, including hypersensitivity, can occur during the post-marketing phase, when vaccines are administered to millions of people. In this article, we will discuss the main aspects of post-vaccine hypersensitivity events of interest to specialists and challenges to recognizing the causal agent and appropriate clinical practice. Potential allergens in routine vaccines will also be reviewed to help health professionals identify patients with a potential risk of ESAVI due to such components. Updating health professionals' knowledge about the safety and benefits of vaccines, particularly in special populations, can contribute to more appropriate clinical practice regarding immunization, reducing the risk of exposure to possible allergens in people with allergies to vaccines or their components, avoiding unnecessary contraindications in coincidental or non-serious events.

Yellow fever vaccination before and during the covid-19 pandemic in Brazil

ABSTRACT OBJECTIVE To analyze the number of yellow fever vaccine doses administered before and during the covid-19 pandemic in Brazil. METHODS This is an ecological, time series study based on data from the National Immunization Program. Differences between the median number of yellow fever vaccine doses administered in Brazil and in its regions before (from April/2019 to March/2020) and after (from April/2020 to March/2021) the implementation of social distancing measures in the country were assessed via the Mann-Whitney test. Prais-Winsten regression models were used for time series analyses. RESULTS We found a reduction in the median number of yellow fever vaccine doses administered in Brazil and in its regions: North (-34.71%), Midwest (-21.72%), South (-63.50%), and Southeast (-34.42%) (p < 0.05). Series showed stationary behavior in Brazil and in its five regions during the covid-19 pandemic (p > 0.05). Brazilian states also showed stationary trends, except for two states which recorded an increasing trend in the number of administered yellow fever vaccine doses, namely: Alagoas State (before: β = 64, p = 0.081; after: β = 897, p = 0.039), which became a yellow fever vaccine recommendation zone, and Roraima State (before: β = 68, p = 0.724; after: β = 150, p = 0.000), which intensified yellow fever vaccinations due to a yellow fever case confirmation in a Venezuelan State in 2020. CONCLUSION The reduced number of yellow fever vaccine doses administered during the covid-19 pandemic in Brazil may favor the reemergence of urban yellow fever cases in the country.

Serious adverse event: late neurotropic disease associated with yellow fever vaccine / Evento adverso grave: doença neurotrópica tardia associada à vacina da febre amarela

ABSTRACT The yellow fever is a systemic disease that was under control due to the effective campaigns against the vector and promotion of vaccines programs. However, since 1999, outbreaks appeared because of inefficient control of the vector, and led to the need of amplifying the immunization in large scale against the yellow fever virus, and consequently, raising the risk of adverse reactions to the vaccine. We report a case of previously healthy infant, who was referred to our care service, after 3 days with fever, chills, nausea and vomits, he received support therapy and was discharged from the hospital. After 24 hours of supportive measures, he was discharge. The patient returned to our service with general condition decline, strabismus, inability to control of cervical musculature and reduced force of the legs. The patient vaccine had received all vaccines from the calendar, and he was vaccinated for yellow fever 20 days before symptoms. During the hospitalization, liquor was collected, and ceftriaxone and aciclovir were administered. After negative cultures from the liquor, the antibiotics were suspended. The computed tomography of patient's brain showed no alterations. Research for antibodies against yellow fever was requested, being positive for IgM in the liquor, and confirming the neurotropic disease associated with the yellow fever vaccine. On the fifth day of hospitalization, the patient showed improvement on the strabismus, cervical tonus, and musculature force. On the tenth day of hospitalization, patient showed complete improvement, and his laboratory exams no alterations. Subsequently, patient was discharged. The vaccine against yellow fever is safe, efficient and highly recommended, however it is not completely free from serious adverse reactions, including death.

RESUMO A febre amarela é uma doença sistêmica que estava controlada graças às efetivas campanhas de combate ao vetor e aos programas de vacinação. Porém, desde 1999, os surtos reiniciaram-se, devido à ineficácia do controle do vetor, levando à necessidade da imunização em larga escala contra o vírus da febre amarela, gerando aumento do risco de ocorrência de reação adversa à vacina. O presente estudo se propôs a relatar o caso de um lactente previamente saudável, que procurou pronto atendimento, pois, há 3 dias, apresentava febre, calafrios, náusea e vômitos. Em 24 horas após medidas de suporte e alta, evoluiu com queda do estado geral, estrabismo, falta de controle da musculatura cervical e redução da força muscular de membros inferiores. O caderno vacinal encontrava-se completo, tendo recebido vacina contra febre amarela há 20 dias. Durante a internação, foi realizada coleta do liquor, e foram administrados ceftriaxona e aciclovir. Após cultura negativa do liquor, o antibiótico foi suspenso. A tomografia computadorizada de crânio não apresentou alterações. Solicitou-se pesquisa de anticorpos contra o vírus da febre amarela no liquor, sendo positiva para IgM e confirmando a doença neurotrópica associada à vacina da febre amarela. A partir do quinto dia de internação, o paciente evoluiu com melhora do estrabismo, do tônus cervical e da força muscular. No décimo dia de internação, apresentou melhora completa do quadro, sem alterações laboratoriais, recebendo alta. A vacina contra febre amarela é segura, eficaz e fortemente recomendada, porém não está completamente isenta de reações adversas graves, inclusive podendo levar a quadros fatais.

Fatores associados à gravidade dos eventos adversos pós-vacinação contra a febre amarela durante o maior surto da doença registrado no Brasil, 2016-2017 / Factores asociados a la gravedad de los eventos adversos posvacunación contra la fiebre amarilla durante el mayor brote de la enfermedad registrado en Brasil, 2016-2017 / Factors associated with severity of adverse events following yellow fever vaccination during the biggest outbreak of the disease recorded in Brazil, 2016-2017

Resumo Objetivo: analisar características, incidência e fatores associados aos eventos adversos graves (EAGs) pós-vacinação contra febre amarela durante surto da doença no Brasil (2016-2017). Métodos: estudo de caso-controle, com dados do Sistema de Informações do Programa Nacional de Imunizações (SI-PNI); foram considerados casos os EAGs, e controles os eventos adversos não graves (EANGs). Resultados: foram analisados 135 casos de EAG e 1.058 controles; dos 135 EAGs, 79 (58,5%) eram homens, e a mediana de idade dos casos, 28 anos (intervalo interquartílico: 9-49); a incidência de EAG em janeiro de 2017 chegou a 1,3 caso por 100 mil doses aplicadas; houve associação estatística com o sexo masculino (odds ratio [OR]=1,73; IC95% 1,20;2,48), ser primovacinado (OR=1,65; IC95% 1,01;2,71), e ter idade ≥60 anos, tomando-se por referência os menores de 5 anos (OR=4,4; p-valor <0,02). Conclusão: EAG pela vacina da febre amarela apresentou maior chance de ocorrer em homens, idosos e primovacinados.

Resumen Objetivo: analizar características, incidencia y factores asociados a eventos adversos graves (EAG) posvacunación contra la fiebre amarilla durante brote de la enfermedad en Brasil (2016-2017). Métodos: estudio de caso-control, con datos del Sistema de Informaciones del Programa Nacional de Inmunizaciones (SI-PNI); se consideraron casos los EAG, y controles los eventos adversos no graves (EANG). Resultados: se analizaron 135 casos de EAG y 1.058 controles; de los 135 EAG, 79 (58,5%) eran hombres, con edad promedio de 28 años [rango intercuartílico: 9-49]; la incidência en enero de 2017 llegó a 1,3 caso por 100 mil dosis aplicadas; ocurrió asociación estadística con el sexo masculino (odds ratio [OR]=1,73 - IC95% 1,20;2,48), ser primovacunado (OR=1,65 - IC95% 1,01;2,71), y tener ≥60 años de edad tomando como referencia a los menores de 5 años (OR=4,4; p-valor <0,02). Conclusión: EAG por la vacuna de la fiebre amarilla presentó mayor probabilidad de ocurrir en hombres, ancianos y primovacunados.

Abstract Objective: to analyze characteristics, incidence and factors associated with serious adverse events (SAEs) following yellow fever vaccination during an outbreak of the disease in Brazil (2016-2017). Methods: this was a case-control study using data from the National Immunization Program Information System (SI-PNI); SAE were considered to be cases, and non-serious adverse events (NSAE) were considered to be controls. Results: we analyzed 135 SAE cases and 1,058 controls; of the 135 SAE, 79 (58.5%) were males and median age was 28 years [09-49]; incidence in January 2017 reached 1.3 case per 100,000 vaccine doses administered; there was statistical association with males (Odds Ratio [OR]=1.73 - 95%CI 1.20;2.48), primary vaccination (OR=1.65 - 95%CI 1.01;2.71), and being 60 years of age or older taking as reference those aged under 5 (OR=4.4; p-value <0.02). Conclusion: SAE owing to yellow fever vaccine showed a greater chance of occurring in men, the elderly and primary vaccination.

Análise das características epidemiológicas da febre amarela em um estado da Região Sudeste do Brasil / Análisis de las características epidemiológicas de la fiebre amarilla en un estado del sureste de Brasil / Analysis of the epidemiological characteristics of yellow fever in a state of southeastern Brazil

Resumo O objetivo do estudo foi analisar o perfil epidemiológico da febre amarela (FA) em Minas Gerais, região sudeste do Brasil. Trata-se de estudo transversal, do tipo série de casos, analisando as notificações de FA entre 03 de janeiro de 2016 a 08 de julho de 2017. Foram notificados 1.677 casos, sendo 427 confirmados e 133 óbitos; com taxa de letalidade de 31,3%. A maioria dos casos foi em homens, adultos jovens, ocupação rural e baixa escolaridade. Em 2016, 28 municípios notificaram epizootias e 1 confirmou morte de macaco por FA. Em 2017, 182 municípios notificaram e 142 confirmaram. No período analisado, a cobertura vacinal média foi inferior a 90% em 96% das Unidades Regionais de Saúde. Destacam-se elevadas porcentagens de campos não preenchidos. Constatou-se elevado número de casos no período analisado. Considerar o perfil epidemiológico da doença no Estado é importante para direcionar as ações de controle, movendo esforços para os grupos mais vulneráveis.

Resumen El objetivo de este estudio fue analizar el perfil epidemiológico de la fiebre amarilla (FA) en Minas Gerais, sureste de Brasil. Se planteó un estudio transversal, de tipo serie de casos, con análisis de las notificaciones entre 03 de enero de 2016 a 08 de julio de 2017. Se notificaron 1.677 casos, siendo 427 confirmados y 133 muertos; con tasa de letalidad de 31,3%. Ocurrió más en hombres jóvenes, con ocupación rural y baja educación. En 2016, 28 municipios tienen epizootias y fue confirmada una muerte de mono por FA. En 2017, se han notificado a 182 municipios y 142 confirmados. La cobertura de vacunación promedio fue inferior al 90% en 96% de las Unidades Regionales de Salud. Incluyen altos porcentajes de campos sin llenar. Tiene alto número de casos en el período analizado. Se concluye que es importante considerar el perfil epidemiológico de la enfermedad en el estado para dirigir las acciones de control, hacia los grupos más vulnerables.

Abstract The objective of this study was to analyze the epidemiological profile of yellow fever (YF) in Minas Gerais, southeastern Brazil. A cross-sectional study was raised, of type series of cases, with analysis of the notifications of between January 03, 2016 to July 08, 2017. 1,677 cases were reported, with 427 confirmed and 133 dead; with a lethality rate of 31,3%. It happened more in young men, rural occupation and low education. In 2016, 28 municipalities have epizootics and one confirmed death of monkey by YF. In 2017, 182 municipalities have notified and 142 confirmed. In the analysis period, the average vaccination coverage was less than 90% in 96% of Regional Health Units. High percentages of unfilled fields were found. It has a high number of cases in the period analyzed. It is concluded that it is important to consider the epidemiological profile of the disease in the State is important to direct the actions of control, moving efforts to the most vulnerable groups.

Segurança da vacina de febre amarela em pacientes comprovadamente alérgicos à proteína do ovo / Safety of yellow fever vaccine in egg allergic patients

Introdução: A vacina de febre amarela, recomendada em áreas endêmicas, é contraindicada em alérgicos à proteína do ovo (APO) por ser cultivada em ovos de galinha embrionados. Objetivo: O objetivo do estudo foi mostrar a segurança da vacina de febre amarela em pacientes comprovadamente APO. Método: Foi realizado estudo prospectivo em hospital quaternário, no período de janeiro a outubro de 2018. Foram incluídos pacientes com APO confirmada por teste de provocação oral (TPO), reação anafilática à proteína do ovo nos últimos 6 meses, ou reação de APO nos últimos 2 meses associada à IgE específica positiva. Todos foram submetidos ao teste de puntura com a vacina na apresentação pura. Se negativo, realizado teste intradérmico (ID) com a vacina na diluição de 1:100. Se ID negativo, vacina aplicada em dose plena. Se teste de puntura ou ID positivo, vacina aplicada fracionada segundo protocolo de dessensibilização. Resultados: Dos 78 pacientes com história presumida de APO, confirmou-se o diagnóstico em 43 (30M:13F, mediana idade 2,7 a): 30 por TPO, 7 com anafilaxia em menos de 6 meses da vacina, e 6 com reação imediata após ingestão do ovo há menos de 2 meses e IgE específica positiva. Durante o TPO, 12 apresentaram anafilaxia, e os demais (18) apresentaram urticária e/ou angioedema ou vômitos. Todos os testes de puntura (43) foram negativos. ID foi negativo em 37 pacientes, que receberam a dose plena da vacina, sem reações. Apenas 6 apresentaram ID positivo e necessitaram dessensibilização para vacina. Metade desses pacientes (3/6) apresentou reações de hipersensibilidade leves e foi tratada com anti-H1 e/ou corticoide oral. O ID positivo foi significativamente relacionado à reação à vacina (p = 0,0016). Conclusão: Concluiuse ser possível vacinar alérgicos a ovo, com um protocolo seguro, mesmo em paciente comprovadamente anafilático. É necessária uma unidade especializada para sua realização, com capacidade de controlar possíveis situações de risco.

Introduction: The yellow fever vaccine (YFV) is recommended in endemic areas, but represents a risk for egg allergic (EA) patients, as it is cultivated in chicken embryos. Objective: This study aimed to describe the outcomes of YFV in patients with confirmed egg allergy. Methods: A prospective study was conducted in a quaternary hospital, from January to October 2018. EA was diagnosed through oral food challenge (OFC) or recent history of anaphylaxis following egg contact in the past 6 months or allergic reaction in the past 2 months with positive specific immunoglobulin E (IgE). Skin prick testing (SPT) with YFV was performed in all participants. If SPT was negative, an intradermal test (IDT) was performed at 1:100 dilution. If IDT was negative, a full dose of YFV was administered. If SPT was positive, the YFV was administered using a graded-dose protocol. Results: Among 78 patients with prior history of EA, 43 were confirmed (30 male to 13 female, median age of 2.7 years). Thirty patients had a positive OFC, seven reported recent anaphylaxis, and six had reactions in the past 2 months with positive specific IgE. During OFC, 12 patients had anaphylaxis and 18 had urticaria and/or angioedema or vomiting. SPT with YFV was negative in all patients (43). IDT was negative in 37 patients, who received a full dose of YFV, uneventfully. Six patients had a positive IDT and received the YFV in graded doses; half of them had a mild reaction controlled with antihistamines and three patients received the vaccine without reactions. Positive IDT was significantly related to vaccine reaction (p=0.0016). Conclusion: The YFV using a specific protocol was safe even in anaphylactic patients. An appropriate setting is required in order to control possible adverse events.

Vacinas experimentais para febre amarela como modelo de estudo de novos adjuvantes / Experimental yellow fever vaccines as a study model for new adjuvants

A vacina de febre amarela atenuada é uma das mais bem-sucedidas já desenvolvidas. Entretanto, restrições de administração para pacientes imunodeprimidos e raros eventos adversos associados são desvantagens que motivam o desenvolvimento de vacinas mais seguras. À medida que aumenta a segurança, a imunogenicidade diminui na ausência de replicação viral. Nesse contexto, adjuvantes são elementos chave na ativação da imunidade inata para modulação das respostas adaptativas e proteção. Adjuvantes de diferentes naturezas e mecanismos de ação têm sido estudados: imunoestimuladores como agonistas de TLR, carreadores de antígenos e agentes de efeito depósito. Nesse estudo pretendemos identificar adjuvantes promissores para o desenvolvimento de novos candidatos vacinais para febre amarela. Para isso, camundongos C57BL/6 foram imunizados com diferentes formulações de antígenos modelo (vírus inativado e proteínas de envelope recombinantes produzidas em diferentes sistemas de expressão) com os adjuvantes: Al(OH)3; Addavax (emulsão baseada em esqualeno); combinações de Al(OH)3 e Flagelina FliC (agonista de TLR5); e CAF01 (nanopartícula) em esquema de 2 doses (D0 e D28) ou 3 doses (D0, D14 e D28). Após a imunização, os camundongos foram desafiados com inóculo letal do vírus de febre amarela por via intracerebral para determinar as taxas de sobrevivência. Os soros foram analisados por ELISA e PRNT50 para detecção dos títulos de IgG total e anticorpos neutralizantes

O vírus FA17DD inativado apresentou o melhor desempenho como antígeno modelo, sendo capaz de induzir 100% de proteção ao desafio após imunização com 2 doses na formulação com o adjuvante Addavax e 70% de proteção na formulação com hidróxido de alumínio. Os demais adjuvantes avaliados (Al(OH)3/ Flagelina FliC e CAF01) não foram capazes de gerar incremento de proteção com os antígenos avaliados. As formulações experimentais com melhor desempenho (FA17DD inativado/Addavax e FA17DD inativado/Al(OH3) foram avaliadas em um segundo ensaio para melhor caracterização das respostas imunológicas envolvidas na proteção. Ambas foram capazes de induzir apenas níveis basais de anticorpos neutralizantes; porém altos títulos de IgG para o vírus da febre amarela com predomínio do subtipo IgG1. A caracterização das respostas celulares locais (ELISpot citocinas e células B) no sítio de inoculação nos tempos pré e pós-desafio revelou níveis superiores de IFNγ nos animais sobreviventes. Após o desafio, todos os animais sobreviventes apresentaram altos títulos de anticorpos neutralizante e IgG total, com incremento do subtipo IgG2a. O uso de Addavax como adjuvante para vacinas não vivas para febre amarela surge como uma alternativa promissora de induzir proteção com menor número de doses. A aplicação do modelo de desafio murino para febre amarela na avaliação de novos adjuvantes se mostrou uma abordagem promissora para a avaliação de novos adjuvantes para uso neste modelo, bem como na geração de conhecimentos extrapoláveis para outros candidatos vacinais em desenvolvimento. (AU)

Brazilian recommendations on the safety and effectiveness of the yellow fever vaccination in patients with chronic immune-mediated inflammatory diseases

Abstract Background: In Brazil, we are facing an alarming epidemic scenario of Yellow fever (YF), which is reaching the most populous areas of the country in unvaccinated people. Vaccination is the only effective tool to prevent YF. In special situations, such as patients with chronic immune-mediated inflammatory diseases (CIMID), undergoing immunosuppressive therapy, as a higher risk of severe adverse events may occur, assessment of the risk-benefit ratio of the yellow fever vaccine (YFV) should be performed on an individual level. Main body of the abstract: Faced with the scarcity of specific orientation on YFV for this special group of patients, the Brazilian Rheumatology Society (BRS) endorsed a project aiming the development of individualized YFV recommendations for patients with CIMID, guided by questions addressed by both medical professionals and patients, followed an internationally validated methodology (GIN-McMaster Guideline Development). Firstly, a systematic review was carried out and an expert panel formed to take part of the decision process, comprising BRS clinical practitioners, as well as individuals from the Brazilian Dermatology Society (BDS), Brazilian Inflammatory Bowel Diseases Study Group (GEDIIB), and specialists on infectious diseases and vaccination (from Tropical Medicine, Infectious Diseases and Immunizations National Societies); in addition, two representatives of patient groups were included as members of the panel. When the quality of the evidence was low or there was a lack of evidence to determine the recommendations, the decisions were based on the expert opinion panel and a Delphi approach was performed. A recommendation was accepted upon achieving ≥80% agreement among the panel, including the patient representatives. As a result, eight recommendations were developed regarding the safety of YFV in patients with CIMID, considering the immunosuppression degree conferred by the treatment used. It was not possible to establish recommendations on the effectiveness of YFV in these patients as there is no consistent evidence to support these recommendations. Conclusion: This paper approaches a real need, assessed by clinicians and patient care groups, to address specific questions on the management of YFV in patients with CIMID living or traveling to YF endemic areas, involving specialists from many areas together with patients, and might have global applicability, contributing to and supporting vaccination practices. We recommended a shared decision-making approach on taking or not the YFV.

Determinants of Compliance of Travelers with Vaccination and Malaria Prophylaxis at a Travel Clinic

BACKGROUND: Pre-travel medical consultation is essential to reduce health impairment during travel. Yellow fever vaccination (YFV) is mandatory to enter some endemic countries. In this study, we evaluated the factors that affect compliance with appropriate prevention of infectious diseases in travelers who visited clinic for YFV. METHODS: For this retrospective study, chart reviews for 658 patients who visited a travel clinic for YFV before travel were conducted. The period of this study was from January 2016 to September 2018. The associations between appropriate vaccination and factors such as travel duration, destination, time of visiting clinic before departure, and purpose of travel were analyzed. RESULTS: Among 658 patients who got YFV during the study period, 344 patients (52.3%) received additional vaccination or malaria prophylaxis following a physician's recommendation. Travelers who visited the clinic more than 21 days before departure were more compliant than those who visited 14 days or fewer before departure (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.23–2.93; P = 0.004). Travelers visiting Africa were more compliant than were those traveling to South and Central America (OR, 1.97; 95% CI, 1.34–2.90; P = 0.001). Travelers in age groups of 40-49 years and over 70 years were less compliant than the 18–29 years old population (OR, 0.51; 95% CI, 0.28–0.93; P = 0.027 and OR, 0.19; 95% CI, 0.04–0.84; P = 0.03, respectively). Also, those who traveled for tour or to visit friends or relatives were more compliant than those who departed for business (OR, 0.77; 95% CI, 1.03–3.56; P = 0.04). CONCLUSION: For appropriate vaccination, pre-travel consultation at least 3 weeks before departure is crucial. Travelers should be aware of required vaccination and malaria prophylaxis before visiting South and Central America and Asia. Plans to enhance compliance of the elderly and business travelers should be contrived.

Fiebre amarilla. Patología de alta significación epidemiológica / Yellow fever. Pathology of high epidemiological significance

Se describen la biología y la epidemiología de la fiebre amarilla (FA), haciendo referencia a la historia de la patología en Argentina y su situación en consonancia con los países vecinos de Brasil, Paraguay y Perú. Se describe su incidencia de los dos últimos años hasta la fecha en Brasil y Perú y su dispersión por infección humana a Chile y algunos países de Europa. Se recomienda para su prevención la implementación de mecanismos de vigilancia epidemiológica, que incluyan educación sanitaria, considerando que la toma de conciencia de la comunidad es trascendente para un adecuado control. (AU)

The biology and the epidemiology of yellow fever are described, with reference to the history of the disease in Argentina and its situation in line with the neighbouring countries of Brazil, Paraguay and Peru. It describes its incidence over the last two years to date in Brazil and Peru and its spread by human infection to Chile and some European countries. Epidemiological surveillance mechanisms are recommended for prevention, including heatlh education, considering that community awareness is important for adequate control. (AU)

Cutaneous lesions caused by the yellow fever vaccine - have you ever seen them?

SUMMARY The Yellow Fever virus was isolated in 1927 and the disease is considered endemic and epidemic in tropical regions of South America and Africa, with thousands of new cases reported annually. Several side effects of the vaccine have already been reported. Although reports of skin rash secondary to the vaccine range from 0 to 15%, no image or detailed description of the lesions were found in the literature. Here we describe a rash on a toddler vaccinated to travel.

RESUMO O vírus da febre amarela foi isolado em 1927, e a doença é considerada endêmica e epidêmica em regiões tropicais da América do Sul e África, com milhares de novos casos relatados anualmente. Vários efeitos colaterais da vacina já foram relatados. Embora os relatos de erupções cutâneas secundárias à vacina variem de 0% a 15%, nenhuma imagem ou descrição detalhada das lesões foi encontrada na literatura. Aqui descrevemos a erupção de uma criança vacinada para viajar.

Yellow fever

Summary The yellow fever (YF) virus is a Flavivirus, transmitted by Haemagogus, Sabethes or Aedes aegypti mosquitoes. The disease is endemic in forest areas in Africa and Latin America leading to epizootics in monkeys that constitute the reservoir of the disease. There are two forms of YF: sylvatic, transmitted accidentally when approaching the forests, and urban, which can be perpetuated by Aedes aegypti. In Brazil, the last case of urban YF occurred in 1942. Since then, there has been an expansion of transmission areas from the North and Midwest regions to the South and Southeast. In 2017, the country faced an important outbreak of the disease mainly in the states of Minas Gerais, Espírito Santo and Rio de Janeiro. In 2018, its reach extended from Minas Gerais toward São Paulo. Yellow fever has an incubation period of 3 to 6 days and sudden onset of symptoms with high fever, myalgia, headache, nausea/vomiting and increased transaminases. The disease ranges from asymptomatic to severe forms. The most serious forms occur in around 15% of those infected, with high lethality rates. These forms lead to renal, hepatic and neurological impairment, and bleeding episodes. Treatment of mild and moderate forms is symptomatic, while severe and malignant forms depend on intensive care. Prevention is achieved by administering the vaccine, which is an effective (immunogenicity at 90-98%) and safe (0.4 severe events per 100,000 doses) measure. In 2018, the first transplants in the world due to YF were performed. There is also an attempt to evaluate the use of active drugs against the virus in order to reduce disease severity.

Single shot of 17D vaccine may not confer life-long protection against yellow fever

The yellow fever (YF) vaccine has been used since the 1930s to prevent YF, which is a severe infectious disease caused by the yellow fever virus (YFV), and mainly transmitted by Culicidae mosquitoes from the genera Aedes and Haemagogus . Until 2013, the World Health Organization (WHO) recommended the administration of a vaccine dose every ten years. A new recommendation of a single vaccine dose to confer life-long protection against YFV infection has since been established. Recent evidence published elsewhere suggests that at least a second dose is needed to fully protect against YF disease. Here, we discuss the feasibility of administering multiple doses, the necessity for a new and modern vaccine, and recommend that the WHO conveys a meeting to discuss YFV vaccination strategies for people living in or travelling to endemic areas.