Zika puzzle in Brazil: peculiar conditions of viral introduction and dissemination: a review

This article discusses the peculiar conditions that favoured the unexpected introduction of Zika virus into the poorest northeastern region of Brazil in 2015, its speed of transmission to other Brazilian states, other Latin American countries and other regions, and the severity of related neurological disorders in newborns and adults. Contrasting with evidence that Zika had so far caused only mild cases in humans in the last six decades, the epidemiological scenario of this outbreak in Brazil indicates dramatic health effects: in 2015, an increase of 20-fold in notified cases of microcephaly and/or central nervous system (CNS) alterations suggestive of Zika congenital infection, followed by an exponential increase in 2016, with 2366 cumulative cases confirmed in the country by the end of December 2016. A significant increase in Guillain-Barré syndrome in adults has also been reported. Factors involved in viral dissemination, neural pathogenesis and routes of transmission in Brazil are examined, such as the role of social and environmental factors and the controversies involved in the hypothesis of antibody-dependent enhancement, to explain the incidence of congenital Zika syndrome in Brazil. Responses to the Zika outbreak and the development of new products are also discussed.

Zika puzzle in Brazil: peculiar conditions of viral introduction and dissemination - A Review.

This article discusses the peculiar conditions that favoured the unexpected introduction of Zika virus into the poorest northeastern region of Brazil in 2015, its speed of transmission to other Brazilian states, other Latin American countries and other regions, and the severity of related neurological disorders in newborns and adults. Contrasting with evidence that Zika had so far caused only mild cases in humans in the last six decades, the epidemiological scenario of this outbreak in Brazil indicates dramatic health effects: in 2015, an increase of 20-fold in notified cases of microcephaly and/or central nervous system (CNS) alterations suggestive of Zika congenital infection, followed by an exponential increase in 2016, with 2366 cumulative cases confirmed in the country by the end of December 2016. A significant increase in Guillain-Barré syndrome in adults has also been reported. Factors involved in viral dissemination, neural pathogenesis and routes of transmission in Brazil are examined, such as the role of social and environmental factors and the controversies involved in the hypothesis of antibody-dependent enhancement, to explain the incidence of congenital Zika syndrome in Brazil. Responses to the Zika outbreak and the development of new products are also discussed.

17DD yellow fever vaccine: a double blind, randomized clinical trial of immunogenicity and safety on a dose-response study.

OBJECTIVE: To verify if the Bio-Manguinhos 17DD yellow fever vaccine (17DD-YFV) used in lower doses is as immunogenic and safe as the current formulation. RESULTS: Doses from 27,476 IU to 587 IU induced similar seroconversion rates and neutralizing antibodies geometric mean titers (GMTs). Immunity of those who seroconverted to YF was maintained for 10 mo. Reactogenicity was low for all groups. METHODS: Young and healthy adult males (n = 900) were recruited and randomized into 6 groups, to receive de-escalating doses of 17DD-YFV, from 27,476 IU to 31 IU. Blood samples were collected before vaccination (for neutralization tests to yellow fever, serology for dengue and clinical chemistry), 3 to 7 d after vaccination (for viremia and clinical chemistry) and 30 d after vaccination (for new yellow fever serology and clinical chemistry). Adverse events diaries were filled out by volunteers during 10 d after vaccination. Volunteers were retested for yellow fever and dengue antibodies 10 mo later. Seropositivity for dengue was found in 87.6% of volunteers before vaccination, but this had no significant influence on conclusions. CONCLUSION: In young healthy adults Bio-Manguinhos/Fiocruz yellow fever vaccine can be used in much lower doses than usual. INTERNATIONAL REGISTER: ISRCTN 38082350.

Mutual interference on the immune response to yellow fever vaccine and a combined vaccine against measles, mumps and rubella.

A randomized trial was conducted to assess the immunogenicity and reactogenicity of yellow fever vaccines (YFV) given either simultaneously in separate injections, or 30 days or more after a combined measles-mumps-rubella (MMR) vaccine. Volunteers were also randomized to YFV produced from 17DD and WHO-17D-213 substrains. The study group comprised 1769 healthy 12-month-old children brought to health care centers in Brasilia for routine vaccination. The reactogenicity was of the type and frequency expected for the vaccines and no severe adverse event was associated to either vaccine. Seroconversion and seropositivity 30 days or more after vaccination against yellow fever was similar across groups defined by YFV substrain. Subjects injected YFV and MMR simultaneously had lower seroconversion rates--90% for rubella, 70% for yellow fever and 61% for mumps--compared with those vaccinated 30 days apart--97% for rubella, 87% for yellow fever and 71% for mumps. Seroconversion rates for measles were higher than 98% in both comparison groups. Geometric mean titers for rubella and for yellow fever were approximately three times higher among those who got the vaccines 30 days apart. For measles and mumps antibodies GMTs were similar across groups. MMR's interference in immune response of YFV and YFV's interference in immune response of rubella and mumps components of MMR had never been reported before but are consistent with previous observations from other live vaccines. These results may affect the recommendations regarding primary vaccination with yellow fever vaccine and MMR.

Incidence of hypotonic-hyporesponsive episodes associated to the combined DTP/Hib vaccine used in Brazilian National Immunizations Program.

OBJECTIVE: To evaluate the safety of a combined diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine used on the Brazilian National Immunizations Program, chiefly the incidence of hypotonic-hyporesponsive episodes. METHOD: Follow-up of a cohort of 21,064 infants (20,925 or 99.7% adhered to the study protocol), within 48 hours of vaccination with diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine in health care units in the City of Rio de Janeiro, to ascertain and investigate spontaneous and solicited severe adverse events. Each child was followed-up for one dose only. RESULTS: The rate of hypotonic-hyporesponsive episodes was 1/1,744 doses (confirmed cases) and 1/1,495 doses (confirmed plus suspect cases). The rate of convulsions was 1/5,231 doses. No cases of apnea were detected. These results are comparable to those found in the literature with diphtheria-tetanus-whole cell pertussis vaccine. CONCLUSION: The diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine under study can be safely used in the National Immunizations Program, according to the current precautions and contraindications.

Incidência de episódios hipotônicos-hiporresponsivos associados à vacina combinada DTP/Hib usada no Programa Nacional de Imunizações / Incidence of hypotonic-hyporesponsive episodes associated to the combined DTP/Hib vaccine used in Brazilian National Immunizations Program

OBJETIVO: Avaliar a segurança da vacina combinada de difteria-tétano-coqueluche de células inteiras e Haemophilus influenzae tipo b usada no Programa Nacional de Imunizações, e em especial a incidência de episódios hipotônicos-hiporresponsivos. MÉTODO: Acompanhamento de uma coorte de 21.064 lactentes (20.925 ou 99,7 por cento aderiram ao protocolo de estudo), nas 48 horas após a aplicação da vacina de difteria, tétano, coqueluche de células inteiras e Haemophilus influenzae tipo b em centros de saúde na cidade do Rio de Janeiro, para determinar e investigar eventos adversos graves, espontâneos e solicitados. Cada criança foi monitorada durante somente uma dose. RESULTADOS: A incidência de episódios hipotônicos-hiporresponsivos foi de 1:1.744 doses (casos confirmados) e de 1:1.495 doses (casos confirmados mais casos suspeitos). A taxa de incidência de convulsões foi de 1:5.231 doses. Não foram detectados casos de apnéia. Esses resultados são comparáveis àqueles relatados na literatura para a vacina contra difteria-tétano-coqueluche de células inteiras. CONCLUSÃO: A vacina contra difteria, tétano, coqueluche de células inteiras e Haemophilus influenzae tipo b em estudo pode ser usada com segurança no Programa Nacional de Imunizações, de acordo com as precauções e contra-indicações correntes.

OBJECTIVE:To evaluate the safety of a combined diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine used on the Brazilian National Immunizations Program, chiefly the incidence of hypotonic-hyporesponsive episodes. METHOD: Follow-up of a cohort of 21,064 infants (20,925 or 99.7 percent adhered to the study protocol), within 48 hours of vaccination with diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine in health care units in the City of Rio de Janeiro, to ascertain and investigate spontaneous and solicited severe adverse events. Each child was followed-up for one dose only. RESULTS: The rate of hypotonic-hyporesponsive episodes was 1/1,744 doses (confirmed cases) and 1/1,495 doses (confirmed plus suspect cases). The rate of convulsions was 1/5,231 doses. No cases of apnea were detected. These results are comparable to those found in the literature with diphtheria-tetanus-whole cell pertussis vaccine. CONCLUSION: The diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine under study can be safely used in the National Immunizations Program, according to the current precautions and contraindications.

Yellow fever vaccination: some thoughts on how much is enough [Vaccine 23 (2005) 3908-3914].

In a recently published article in this journal, Massad et al. contraindicates yellow fever vaccination to persons 60 years or older, considering that the risk of serious adverse events is higher for this age class. The conclusion was based on the input of available data on age-related probabilities of developing serious adverse events in the United States, as well on other data not firmly established. We consider such contraindication inadequate, because the data input has limitations, higher letality of wild-type yellow fever infection in older adults, risk of introduction of yellow fever by travelers into new countries, lower risk of vaccine adverse events in revaccinated or immune people in endemic countries, and the experience of Brazil, with only one suspect case of associated viscerotropic disease in an individual older than 60 years. The model proposed by Massad et al. is useful but can lead to different conclusions, depending on the epidemiological context and individual risk profile.

Estudo multicêntrico de imunogenicidade e reatogenicidade de vacinas contra hepatite B: informe preliminar / Multicenter study on immunogenicity and reactogenicity of vaccines against hepatitis B: a preliminary report

O Instituto Butantan desenvolveu uma vacina recombinante contra a hepatitie B (Butang). Visando subsidiar o Programa Nacional de Imunizações (PNI)do Ministério da Saúde quanto à incorporação do produto na rotina de vacinação, foi realizado um ensaio clínico com o objetivo de determinar a imunogenicidade e segurança da vacina Butang em indivíduos menores de 41 anos de idade

[Technological development: a weak link in vaccine innovation in Brazil]. / Desenvolvimento tecnológico: elo deficiente na inovação tecnológica de vacinas no Brasil.

In very recent years, the federal government has launched important initiatives mean to strengthen science, technology, and innovation in Brazil and thus enhance the results of technological innovation in key areas of the country's economy. Yet these initiatives have not been enough to reduce Brazil's heavy dependence on goods and technology from more developed nations. The article describes the current state of vaccination, production, and technological development of vaccines both internationally and nationally. Some thoughts are also offered on the complexity of vaccine innovation and the various stages whose completion is essential to the whole process of technological development. An analysis is made of the parameters and factors involved in each stage; technical requirements for facilities and equipment; good manufacturing practice guidelines; organizational, infrastructural, and managerial needs; and the lengthy time periods adn high costs entailed in these activities.