Navegando por Assunto "Vacinas"

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Acesso aberto (Open Access)
Eficácia e segurança de uma vacina oral de rotavírus humano atenuado contra gastroenterite grave por rotavírus, durante os primeiros dois anos de vida em crianças em Belém, Pará, Brasil
(Universidade Federal do Pará, 2009) JUSTINO, Maria Cleonice Aguiar; ARAÚJO, Eliete da Cunha; http://lattes.cnpq.br/5906453187927460; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
Rotaviruses are recognised as the leading cause of severe gastroenteritis in children aged less than five years in both developed and developing countries, with highest incidence rates between 6 and 24 months of life. On a global scale, recent estimates indicate that annually rotaviruses cause at least 500,000 deaths. A large phase III clinical trial was undertaken in 11 Latin American countries and Finland with an attenuated, human-derived vaccine strain, including recruitment of more than 63,000 children. This was a randomised, double-blind, placebo-controlled trial in which more than 63,000 infants were randomly assigned to receive two oral doses of either RIX4414 or placebo at a proportion of 1:1. The main purposed of this study was to evaluate both protective efficacy and safety of RIX4414. As part of the original study, 3,218 children were enrolled in Belém, Pará, to whom two doses of either vaccine or placebo were administered at 2 and 4 months of age. A subset of infants (n = 653) was evaluated throughout 1 – 2 years in order to assess efficacy of RIX4414 vaccine. Overall, 37 gastroenteritis episodes of severe rotavirus gastroenteritis were recorded of which 75.6% (28/37) and 24% (9/37) in the placebo and vaccine recipients, respectively. The level of rotavirus vaccine protection was higher [83% (CI95% 22 – 96)] against very severe rotavirus gastroenteritis, yielding a ≥ 15 score as calculated with a 20-point Ruuska & Vesikari scale. The cumulative hazard of a first episode of severe gastroenteritis was about four-fold lower in the vaccine group throughout the 2-years’ efficacy period, as compared to the placebo group. The protection rates against severe gastroenteritis caused by G1- and- non-G1 serotypes were 51% (CI95% -30-81) and 82% (CI95% 37-95), respectively, denoting efficacies against rotavirus strains both homologous and heterologous to the vaccine strain. Of importance, the vaccine afforded significant protection [93% (CI95%47-99)] against G9 serotype which has been regarded as a globally emergent strain, besides of being related to more severe gastroenteritis. Also reflecting a vaccine efficacy, there was a significant reduction, by 35.3% (CI95% 11.6-52.9), in the rate of allcause hospitalisation for gastroenteritis, a finding of potential major public health impact. With regards to safety of RIX4414 vaccine, there were no overall statistically significant differences when the rates of serious adverse events were compared for vaccine group and placebo group. No cases of intussusception were reported during the entire follow-up period, through broad and active surveillance in paediatric clinics in the study area. Results obtained in this study confirm previous findings from worldwide several multi-centric trials that sustain both protective efficacy and safety of RIX4414 when administered in a 2-dose schema to healthy infants.
Acesso aberto (Open Access)
Malaria vaccine: roadblocks and possible solutions
(1998-03) SOARES, Irene da Silva; RODRIGUES, Mauricio Martins
Malaria remains the most prevalent and devastating parasitic disease worldwide. Vaccination is considered to be an approach that will complement other strategies for prevention and control of the disease in the future. In the last 10 years, intense studies aimed at the development of a malaria vaccine have provided important knowledge of the nature of the host immunological mechanisms of protection and their respective target antigens. It became well established that protective immune responses can be generated against the distinct stages of Plasmodium. However, in general, protective immune responses are directed at stage-specific antigens. The elucidation of the primary structure of these antigens made possible the generation of synthetic and recombinant proteins that are being extensively used in experimental immunizations against the infection. Today, several epitopes of limited polymorphism have been described and protective immunity can be generated by immunization with them. These epitopes are being tested as primary candidates for a subunit vaccine against malaria. Here we critically review the major roadblocks for the development of a malaria vaccine and provide some insight on how these problems are being solved.
Acesso aberto (Open Access)
Resposta imune humoral de bubalinos (Bubalus bubalis) vacinados pela cepa B19 de Brucella abortus
(Universidade Federal do Pará, 2013-08-31) PEREIRA, Ana Patrícia Moreira; CASSEB, Alexandre do Rosário; http://lattes.cnpq.br/6525374874057337; PEREIRA, Washington Luiz Assunção; http://lattes.cnpq.br/9266281009742277
Brucellosis is spread throughout the country, with the highest prevalence for the strain Brucella abortus that despite being endemic presents unevenly among different regions of Brazil. This study aims to evaluate the humoral and immune response of buffalo calves raised in the Middle Amazon Mesoregion, Pará state, vaccinated with B19 strain of B. abortus according the age recommended by the National Program for the Control and Eradication of Brucellosis and Tuberculosis (PNCEBT). Thirty-six female (test group) and six males (control group) aged 3-8 months were selected and monitored. On day 0 of the experiment, blood was collected from all animals, then all females received commercial vaccine with standard-dose sample B19 as recommended by PNCEBT with subsequent blood samples were taken at 30, 60, 90, 120, 150, 180, 210, 330, 360 and 390 days, respectively. The blood serums were evaluated for evidence of agglutination screening through Buffered Acidified Antigen - AAT and the confirmatory test through 2 Mercaptoethanol - 2ME. The results for all samples collected on day 0 were negative in the reaction, however at 30 and 60 days all females were 100% positive through test reaction AAT and titration 1:200, starting the decline through the titration at 90 days in both events. Females at 210 days still present reagents with similar results in both tests, however only one animal remained reactive in both tests up to 360 days. After 390 days of the begin of the experiment 100% of the females had a negative reaction in both events and throughout the experiment males were negative. Thus, by the evaluation of results, vaccination was effective for immunization, as well as an important tool in the prophylaxis of brucellosis in the species studied, as well as the tests applied to the diagnosis of this disease in buffaloes species at regional level.
Acesso aberto (Open Access)
Segurança, imunogenicidade e eficácia protetora de duas doses da vacina RIX4414 contendo rotavírus atenuado de origem humana
(2007-06) ARAÚJO, Eliete da Cunha; CLEMENS, Sue Ann C.; OLIVEIRA, Consuelo Silva de; JUSTINO, Maria Cleonice Aguiar; RUBIO, Pilar; GABBAY, Yvone Benchimol; SILVA, Veronilce Borges da; MASCARENHAS, Joana D'Arc Pereira; CAVALCANTE, Vânia Lúcia Noronha; CLEMENS, Ralf; GUSMÃO, Rosa Helena Porto; SANCHEZ, Nervo; MONTEIRO, Talita Antonia Furtado; LINHARES, Alexandre da Costa
Objective: To determine the safety, immunogenicity and efficacy of two doses of rotavirus vaccine in healthy Brazilian infants. Methods: A randomized, multicenter, double-blind, placebo-controlled trial was conducted in Brazil, Mexico and Venezuela. Infants received two oral doses of vaccine or placebo at 2 and 4 months of age, concurrently with routine immunizations, except for oral poliomyelitis vaccine (OPV). This paper reports results from Belém, Brazil, where the number of subjects per group and the viral vaccine titers were: 194 (104.7 focus forming units – FFU), 196 (105.2 FFU), 194 (105.8 FFU) and 194 (placebo). Anti-rotavirus (anti-RV) antibody response was assessed in 307 subjects. Clinical severity of gastroenteritis episodes was measured using a 20-point scoring system with a score of ≥ 11 defined as severe GE. Results: The rates of solicited general symptoms were similar in vaccine and placebo recipients. At 2 months after the second dose, a serum IgA response to RV occurred in 54.7 to 74.4% of vaccinees. No interference was seen in the immunogenicity of routine vaccines. Vaccine efficacy against any rotavirus gastroenteritis (RVGE) was 63.5% (95%CI 20.8-84.4) for the highest concentration (105.8 FFU). Efficacy was 81.5% (95%CI 44.5-95.4) against severe RVGE. At its highest concentration (105.8 FFU), RIX4414 provided 79.8% (95%CI 26.4-96.3) protection against severe RVGE by G9 strain. Conclusions: RIX4414 was highly immunogenic with a low reactogenicity profile and did not interfere with seroresponse to diptheria, tetanus, pertussis, hepatitis B and Hib antigens. Two doses of RIX4414 provided significant protection against severe GE caused by RV.
Acesso aberto (Open Access)
Sistemas de liberação controlada de quitosana contendo antigeno capsular Vi de Salmonella Typhi
(Universidade Federal do Pará, 2012-08-31) SILVA, Raimundo Lopes da; TEIXEIRA, Francisco Martins; http://lattes.cnpq.br/7648303522085382; COSTA, Roseane Maria Ribeiro; http://lattes.cnpq.br/0537372052713559
The use of the Vi antigen in vaccines is very promising because this provides a high level of immunity in parenteral vaccines. The need for the search for alternatives for administration of vaccines has led to the application of technology controlled release of drugs in the field of immunization. In such controlled delivery systems, the doses are decreased, but the period of immunity increases, extending the amount of antigen released over time. This study aimed to develop and characterize a controlled delivery system containing Vi antigen, using as disseminator polymer chitosan. The techniques of H-1 NMR and infrared spectroscopy showed that the method of extracting the Vi antigen used was qualitatively satisfactory. The characterization of chitosan and nanoparticles by tests thermal analysis showed greater stability of the particles in relation to chitosan, besides increasing the degradation temperature of the nanoparticles increases as the concentration of chitosan. Regarding the zeta potential nanoparticles were all positive charges at pH7.2, while the particles were smaller size as they increased the amount of chitosan in the system. In transmission electron microscopy showed the particles are morphologically homogeneous and spherical. In the adsorption kinetics of antigen contained in solution, suffered a 55% adsorption of the particles of chitosan. With this, we observed that it is possible to create a controlled delivery system involving nanoparticles of chitosan and Vi antigen of Salmonella enterica serotype Typhi.
Acesso aberto (Open Access)
Vamos à vacina?: doenças, saúde e práticas médico-sanitárias em Belém (1904 a 1911)
(Universidade Federal do Pará, 2006-04-28) AMARAL, Alexandre Souza; SARGES, Maria de Nazaré dos Santos; http://lattes.cnpq.br/2076421409418420
Since the end of the nineteenth century until the beginning of the twentieth century, Belém, according to the intendant Antonio Lemos, was known as the “paraense necropolis”. Illnesses and epidemics have been in the focus of the discussion of medical-sanitary practices. The doctor’s hygienism has become recurrent speech of intervention in the inhabitants’ daily Space, where the prophylaxes’ campaigns were considered responsible for the cure of the city. The proposed actions by medical doctors create tensions among inhabitants and public Authorities in face of the alliance between the medical knowledge and the government, topic Which I have chosen to analyze in order to explain the day-to-day of the coercive actions, with The intention of understand such alliance. Analyzing medical articles in the press, literary theoretical, journalists, politicians, Medical reports, government’s messages, photographs and charges, it was possible to follow The meanings attributed by the contemporaries related to epidemics as the smallpox, Tuberculosis and yellow fever, for example, considering the medical knowledge. The Belle Époque in Belém it was no more considered in this paper as a historiographical crystal, in face Of the adversity of anonymous citizens’ way of life. The city has become a laboratory of Experiences that propose to cure it in order to reach such divulged economic development. The city has been left in the doctor’s hands. The consolidation of this alliance has been given To the well-known sanitarian Oswaldo Cruz, that arrived in Belém City in 1910 to fight Against the yellow fever with the complete support of the governor João Coelho. On the other Hand, the cure of the city or “paraense necropolis” has brought out larger significances, Among them, coincidentally, the burial of the amarílico evil, as well as, the burial of colonel Antonio Lemos’ oligarchy.