ABSTRACT Background: Zika, a disease caused by Zika virus infections, has recently emerged and caused outbreaks in many parts of the world. The clinical manifestations of Zika are usually mild, mostly presenting as an exanthematic febrile disease, but on some occasions, it might be associated with microcephaly after intrauterine infection, and Guillain-Barré Syndrome. Zika virus is primarily transmitted by mosquito bites, but other means of transmission have been described, and potential risk for blood transmission has been reported in French Polynesia and Brazil. Methods: To investigate the risk of Zika virus infection after a blood transfusion in an area of Brazil where a possible transmission by a platelet concentrate has been described. Using a mini-pool format, 1857 blood donations were evaluated by real-time reverse transcriptase polymerase chain reaction designed to detect Zika virus RNA. Results: After testing samples individually from positive mini-pools, the prevalence of Zika virus RNA was only 0.16%, a result probably associated to the low circulation of this virus in the study area. In addition, it was evident that the implementation of post-surveillance programs is important to detect Zika virus infections in blood donors, as the post-donation surveillance program detected two blood donors with the disease in this study. Conclusion: This study shows that the risk for Zika virus transmission by blood transfusion is real, even in regions with a low circulation of the disease, but the combination of the detection of Zika virus RNA by polymerase chain reaction and post-donation surveillance might reduce the risk of transmission by blood transfusions.

Dengue, doença causada por qualquer um dos quatro sorotipos dos vírus dengue, é atualmente a mais importante doença viral transmitida por artrópodos em todo o mundo, tanto em termos de morbidade como de mortalidade. A infecção por estes vírus causa grande variedade de manifestações clínicas, desde infecções assintomáticas até doenças graves com envolvimento de diversos órgãos. As formas graves da dengue são mais frequentes em infecções secundárias por sorotipos diferentes e, por esta razão, a vacina contra a dengue deve ser tetravalente. Embora várias estratégias tenham sido usadas no desenvolvimento de vacinas contra a dengue, não há ainda nenhuma vacina disponível, particularmente por problemas no desenvolvimento de uma vacina tetravalente. Aqui, descreve-se brevemente os candidatos vacinais disponíveis e a capacidade de eles induzirem resposta imune protetora contra novas infecções. Ainda, discutimos os problemas e as possibilidades de liberação, para uso em seres humanos, de qualquer uma das vacinas em fase final de desenvolvimento

Dengue, a disease caused by any of the four serotypes of dengue viruses, is the most important arthropod-borne viral disease in the world in terms of both morbidity and mortality. The infection by these viruses induces a plethora of clinical manifestations ranging from asymptomatic infections to severe diseases with involvement of several organs. Severe forms of the disease are more frequent in secondary infections by distinct serotypes and, consequently, a dengue vaccine must be tetravalent. Although several approaches have been used on the vaccine development, no vaccine is available against these viruses, especially because of problems on the development of a tetravalent vaccine. Here, we describe briefly the vaccine candidates available and their ability to elicit a protective immune response. We also discuss the problems and possibilities of any of the vaccines in final development stage reaching the market for human use.

Dengue, doença causada por qualquer um dos quatro sorotipos dos vírus dengue, é atualmente a mais importante doença viral transmitida por artrópodos em todo o mundo, tanto em termos de morbidade como de mortalidade. A infecção por estes vírus causa grande variedade de manifestações clínicas, desde infecções assintomáticas até doenças graves com envolvimento de diversos órgãos. As formas graves da dengue são mais frequentes em infecções secundárias por sorotipos diferentes e, por esta razão, a vacina contra a dengue deve ser tetravalente. Embora várias estratégias tenham sido usadas no desenvolvimento de vacinas contra a dengue, não há ainda nenhuma vacina disponível, particularmente por problemas no desenvolvimento de uma vacina tetravalente. Aqui, descreve-se brevemente os candidatos vacinais disponíveis e a capacidade de eles induzirem resposta imune protetora contra novas infecções. Ainda, discutimos os problemas e as possibilidades de liberação, para uso em seres humanos, de qualquer uma das vacinas em fase final de desenvolvimento

Dengue, a disease caused by any of the four serotypes of dengue viruses, is the most important arthropod-borne viral disease in the world in terms of both morbidity and mortality. The infection by these viruses induces a plethora of clinical manifestations ranging from asymptomatic infections to severe diseases with involvement of several organs. Severe forms of the disease are more frequent in secondary infections by distinct serotypes and, consequently, a dengue vaccine must be tetravalent. Although several approaches have been used on the vaccine development, no vaccine is available against these viruses, especially because of problems on the development of a tetravalent vaccine. Here, we describe briefly the vaccine candidates available and their ability to elicit a protective immune response. We also discuss the problems and possibilities of any of the vaccines in final development stage reaching the market for human use.