Navegando por Assunto "Vacina"

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Acesso aberto (Open Access)
Avaliação temporal e genética do rotavírus genótipo G2 circulante na Região Norte do Brasil antes e após a introdução da vacina contra rotavírus
(Universidade Federal do Pará, 2016-10-31) OLIVEIRA, Alessilva do Socorro Lima de; MASCARENHAS, Joana D'Arc Pereira; http://lattes.cnpq.br/5156164089432435
Rotavirus group A (RVA) is the most important cause of diarrhea, accounting for about 40% of morbidity and mortality related to this disease in children around the world before the introduction of the vaccine. After the introduction of the vaccine against the RVA in Brazil in 2006 genotype G2RVA he rose again, being detected in up to 82% of children under five years of age performed post vaccination studies, leading to questions about the protection afforded by the vaccine facing the G2 type, as well as the occurrence of a selective pressure vaccine. Little is known about the evolution and diversity of G2 genotype and the possible influence of the vaccine on this. To provide a better understanding of the flow and genetic diversity of RVA genotype G2, we perform the time of circulation analysis of genotype over 31 years and analysis of structural and non-structural genes from samples that have circulated over 20 years in northern region of Brazil. The temporal assessment of movement of different genotype circulating in this region has observed that the G2 type RVA presented over the years a cyclical pattern of occurrence that did emerge in a post deployment of the vaccine scenario, suggesting a natural fluctuation due to variations natural occurring over time. Phylogenetic analyzes showed that for VP7 lines G2 there is a continuous, responsible for a movement of rotation in the lines being detected two lines and three sublineages over 20 years. Three important substitutions in antigenic regions of VP7 (A87T, D96N and S213D) were identified in samples that circulated from the 90. These changes may have increased the capacity of the circulating strains in environments where there is vaccine coverage for RVA. All G2P[4] strains analyzed revealed a DS-1-like genome constellation: I2-R2-C2-M2-A2-N2-T2-E2-H2. However, several viral variants circulated during the study period. No differences were observed in the antigenic sites of the VP8 * and VP7 proteins between samples that circulated in the period before and after the introduction of the vaccine. For VP2 and VP3 genes was evident in some samples a strong correlation with animal genes. This study provides evidence of genetic diversity in G2 genotype RVA, suggesting that this type has natural characteristics fluctuation and its emergence after the implementation period of the vaccine is more directly associated with ecological characteristics of the virus than a vaccine pressure.
Acesso aberto (Open Access)
Vacinas contra rotavírus e papilomavírus humano (HPV)
(Universidade Federal do Pará, 2016-07) LINHARES, Alexandre da Costa; VILLA, Luisa Lina
Objective: To briefly review strategies aimed at the development of rotavirus and HPV vaccines, with emphasis on the current status of studies assessing the safety, reactogenicity, immunogenicity and efficacy of recently developed vaccines. Sources of data: This review focuses on articles published from 1996 to 2006, mainly those from the last five years, with special emphasis on data obtained from recently completed studies involving a new live attenuated human rotavirus vaccine and a virus-like particle (HPV) vaccine. Summary of the findings: Strategies for developing rotavirus vaccines ranged from Jennerian approaches to the new human-derived rotavirus vaccine. Currently, two rotavirus vaccines are recognized as both efficacious and safe: a pentavalent human-bovine reassortant vaccine and a vaccine derived from an attenuated rotavirus of human origin. The second of these has been evaluated in more than 70,000 infants all over the world. Prophylactic vaccines against HPV have been tested in more than 25,000 young individuals around the world. Results from phase II and III clinical studies indicate that such vaccines against the most common types of HPV, those linked to both genital warts and 70% of cervical cancers, are safe and highly efficacious. Conclusions: A future rotavirus immunization program covering 60 to 80% of infants worldwide is likely to reduce by at least 50% the number of rotavirus-associated hospitalizations and deaths. It is also reasonable to expect that implementation of HPV prophylactic vaccines will reduce the burden of the HPV-related diseases that presently impact millions of people around the world.