Vigilância de eventos adversos pós-vacinação e segurança de programas de imunização

O objetivo da revisão foi analisar aspectos conceituais e operacionais de sistemas de vigilância de eventos adversos pós-vacina. Foram incluídos artigos disponíveis em formato eletrônico, publicados entre 1985 e 2009, selecionados nas bases Medline/PubMed, com as palavras-chave: "adverse events following vaccine", "adverse events following vaccine surveillance", "post-marketing surveillance" e "safety vaccine" e "Phase IV clinical trials", e excluídos aqueles com foco em tipos específicos desses eventos. Foram apontados os principais aspectos que justificam a importância dos eventos adversos pós-vacina em saúde pública, os instrumentos que garantem a segurança das vacinas e as finalidades, atributos, tipos, interpretações de dados, limitações e novos desafios da vigilância de eventos adversos pós-vacina, bem como estratégias para aumentar sua sensibilidade. A revisão é concluída com desafios para os próximos anos, visando à segurança e confiabilidade dos programas de vacinação.

Cobertura vacinal em menores de dois anos a partir de registro informatizado de imunização em Curitiba, PR

OBJETIVO: Avaliar o programa de imunização de crianças de 12 e de 24 meses de idade, com base no registro informatizado de imunização. MÉTODOS: Estudo descritivo em amostra probabilística de 2.637 crianças nascidas em 2002 e residentes em Curitiba, PR. As fontes de dados foram: registro informatizado de imunização do município, Sistema de Informação de Nascidos Vivos e inquérito domiciliar para casos com registro incompleto. As coberturas foram estimadas aos 12 e aos 24 meses de vida e analisadas segundo características socioeconômicas de cada distrito sanitário e o vínculo das crianças aos serviços de saúde. Foram analisadas a abrangência, completude e duplicidades do registro informatizado de imunização. RESULTADOS: A cobertura do esquema de imunização foi de 95,3% aos 12 meses sem diferenças entre os distritos e de 90,3% aos 24 meses, tendo sido mais elevada em um distrito com piores indicadores socioeconômicos (p = 0,01). A proporção de vacinas, segundo o tipo, aplicadas antes e após a idade recomendada foi de até 0,9% e até 32,2%, respectivamente. A cobertura do registro informatizado de imunização foi de 98% na amostra estudada, o sub-registro de doses de vacinas foi de 11% e a duplicidade de registro foi de 20,6%. Os grupos que apresentaram maiores coberturas foram: crianças com cadastro definitivo, aquelas com três ou mais consultas pelo Sistema Único de Saúde e as atendidas em Unidades Básicas de Saúde que adotam plenamente a Estratégia de Saúde da Família. CONCLUSÕES: A cobertura vacinal em Curitiba mostrou-se elevada e homogênea entre os distritos, e o vínculo com os serviços de saúde foi fator importante para tais resultados. O registro informatizado de imunização mostrou-se útil no monitoramento da cobertura vacinal; no entanto, é importante a prévia avaliação do seu custo-efetividade para que seja amplamente utilizado pelo Programa Nacional de Imunização.

Characterization of Vibrio Parahaemolyticus isolated from oysters and mussels in São Paulo, Brazil

Vibrio parahaemolyticus is a marine bacterium, responsible for gastroenteritis in humans. Most of the clinical isolates produce thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) encoded by tdh and trh genes respectively. In this study, twenty-three V. parahaemolyticus, previously isolated from oysters and mussels were analyzed by PCR using specific primers for the 16S rRNA and virulence genes (tdh, trh and tlh) and for resistance to different classes of antibiotics and PFGE. Nineteen isolates were confirmed by PCR as V. parahaemolyticus. The tlh gene was present in 100% of isolates, the tdh gene was identified in two (10.5%) isolates, whereas the gene trh was not detected. Each isolate was resistant to at least one of the nine antimicrobials tested. Additionally, all isolates possessed the blaTEM-116 gene. The presence of this gene in V. parahaemolyticus indicates the possibility of spreading this gene in the environment. Atypical strains of V. parahaemolyticus were also detected in this study.

Pathogenicity of different rabies virus isolates and protection test in vaccinated mice

This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD50/0.03mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0% for the Desmodus rotundus isolate; 50.0% for dog and Nyctinomops laticaudatus isolates; 40.0% for Artibeus lituratus isolate; 9.5% Molossus molossus isolate; and 5.2% for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.

Diversidade genotípica de rotavírus suínos no Estado de São Paulo

Rotavírus é uma das causas mais comuns de diarréia tanto em humanos quanto em diferentes espécies animais. Foi conduzido um estudo transversal a partir de 144 amostras fecais diarréicas colhidas de leitões, provenientes de 16 criações comerciais distribuídas por 10 municípios do Estado de São Paulo, Brasil, com o objetivo de se detectar a ocorrência de rotavírus e realizar sua caracterização molecular quanto seus genotipos G e P. Um total de 43 amostras (29,86%) foram positivas para rotavírus por Eletroforese em Gel de Poliacrilamida (PAGE) e ELISA, num esquema de triagem em paralelo. A caracterização mediante reações do tipo nested-multiplex RT-PCR demonstrou que, isoladamente, o genotipo P[6] foi o mais frequente, detectado em 25,58% das amostras, seguido pelo P[1] (11,63%) e P[7] (9,3%). Infecções concomitantes de genotipos P[6]+P[7] (9,3%), P[1]+P[6] (4,65%), P[1]+P[6]+P[7] (2,33%) foram também observadas. Analogamente, o genotipo G[5] foi detectado em 30,23% das amostras, seguido pelo G[10] (20,93%) e G[6] (4,65%) e G[5]+G[10] (18,6%). O genotipo G[5]P[6] foi o mais frequente (11,63%), porém outras combinações e amostras não tipificáveis também foram observadas. Considerando-se a diversidade de rotavírus suínos encontrada na população estudada, medidas profiláticas específicas devem levar em conta, para sua efetividade, o grau de proteção cruzada entre os genotipos presentes nas formulações vacinais e aqueles que realmente são circulantes numa região.

Comparison of agglutinating and neutralizing antibodies to serovar hardjo in sows immunized with two commercial whole culture polivalent anti-leptospira bacterins

It was performed the comparison of the intensity and duration of agglutinating and neutralizing antibodies to serovar Hardjo in swines vaccinated with two commercial anti-leptospira bacterins. Sows no reactive to 24 Leptospira sp serovars in the microscopic agglutination test (MAT) were divided in three groups: Group A (n=08): received two vaccine A doses with 30 days interval, Group B (n=08) two vaccine B doses with 30 days interval and Group C (n=08): control no vaccinated against leptospirosis.Blood samples were collected each 30 days during six months following the first vaccination. The sera were tested by MAT and growth inhibition test (GIT) to serovar Hardjo in order to evaluate respectively agglutinating and neutralizing antibodies. It was found that neutralizing antibodies persisted for a longer time than the agglutinating ones and that the absence of agglutinating antibodies does not means in the absence of the neutralizing. The peaks of agglutinating antibodies was obtained at least 30 days earlier than that produced by neutralizing. The duration of both kinds of antibodies measured differed between the two bacterines tested. The period for inducing neutralizing antibodies against serovar Hardjo indicated that gilts must be immunized with two doses of whole culture anti-leptospira bacterines applied 30 days each other at least 90 days before the first mating. For the maintenance of hight levels of neutralizing antibodies the revaccinations must be performed every six months after the first vaccination.

Avaliação da imunidade passiva em bezerros nascidos de vacas imunizadas com vacina contra rotavírus

Com o objetivo de monitorar a imunidade passiva em bezerros alimentados com colostro de vacas imunizadas e não imunizadas com vacina contra rotavírus, foram determinados títulos de anticorpos em amostras de sangue e colostro de 26 vacas da raça Holandesa no dia do parto e de seus bezerros, à zero, às 24, 48 horas e aos sete, 14, 21, 28 dias de idade, pelo ensaio imunoenzimático. Tanto no soro sangüíneo como no colostro, os títulos dos isótipos IgG, IgG1 e IgG2 foram mais elevados no grupo dos animais vacinados, porém somente no colostro o aumento foi significativo. Os bezerros alimentados com o colostro das vacas vacinadas apresentaram títulos mais altos dos isótipos IgG, IgG1, IgG2, IgA e IgM, após a ingestão do colostro, sendo constatado aumento significativo apenas para os títulos do isótipo IgG2. Amostras positivas para rotavírus foram detectadas nos dois grupos experimentais a partir dos sete dias de idade. A vacinação materna não protegeu efetivamente os bezerros das infecções naturais por rotavírus, pois, apesar de aumentar os títulos séricos de anticorpos anti-rotavírus nos animais vacinados, não foi capaz de impedir a ocorrência da rotavirose nos bezerros alimentados com o colostro das vacas imunizadas.

Sistemas informatizados de registro de imunização: uma revisão com enfoque na saúde infantil

São apresentadas diferentes experiências e metodologias empregadas por registros informatizados de imunização (RII), no enfoque da saúde infantil. O levantamento bibliográfico abrangeu publicações de 1990 a 2006, existentes nas bases MEDLINE, SciELO, PubMed e EMBASE. Outros sítios eletrônicos de organizações nacionais e internacionais de saúde foram pesquisados. Em virtude da ausência de publicações sobre RII no Brasil, as fontes de informação foram a Coordenação Nacional e as Coordenações Estaduais do Programa Nacional de Imunizações, além do Departamento de Informática do Sistema Único de Saúde. Selecionaram-se apenas artigos que abordam RII em saúde infantil. Foram localizados 109 artigos publicados em 35 revistas especializadas. São apresentados aspectos históricos e conceituais, objetivos, funções, relevância e indicadores de desempenho e de custo-efetividade, além das próprias limitações dos RII, assim como experiências em países selecionados, inclusive no Brasil. Os RII integrados a outros sistemas de informação vêm sendo aplicados como importante instrumento para a identificação de populações com menor acesso ou adesão aos programas de vacinação e em sistemas de vigilância ativa de eventos adversos pós-vacina

Surveillance for adverse events after DTwP/Hib vaccination in Brazil: sensitivity and factors associated with reporting

We estimated the sensitivity, i.e., the proportion of all cases of adverse events following immunization (AEFIs) reported to the Brazilian passive surveillance for adverse events following immunization (PSAEFI) with the diphtheria-tetanus-whole-cell pertussis-Haemophilus influenzae type b (DTwP-Hib) vaccine, as well as investigating factors associated with AEFIs reporting. During 2003–2004, 8303 AEFIs associated with DTwP-Hib were reported; hypotonic-hyporesponsive episodes (HHEs), fever and convulsions being the most common. Cure without sequel was achieved in 98.4 per cent of the cases. The mean sensitivity of the PSAEFI was 22.3 per cent and 31.6 per cent, respectively, for HHE and convulsions, varying widely among states. Reporting rates correlated positively with the Human Development Index and coverage of adequate prenatal care, correlating negatively with infant mortality rates. Quality of life indicators and the degree of organization of health services are associated with greater PSAEFI sensitivity. In addition to consistently describing the principal AEFIs, PSAEFI showed the DTwP/Hib vaccine to be safe and allayed public fears related to its use

Investigation of measles IgM-seropositive cases of febrile rash illnesses in the absence of documented measles virus transmission, State of São Paulo, Brazil, 2000-2004

Introdução: Revisar os casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no estado de São Paulo, Brasil, durante os cinco anos seguidos a interrupção da transmissão do vírus do sarampo. Métodos: Nós revisamos 463 casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no estado de São Paulo, Brasil, de 2000 a 2004. Indivíduos vacinados contra o sarampo 56 dias antes da coleta de amostra foram considerados expostos à vacina. Soros da fase aguda e de convalescença foram testados para a evidência de infecção de sarampo, rubéola, parvovírus B19 e herpes vírus 6. Na ausência de soroconversão para imunoglobulina G contra o sarampo, casos com IgM reagente contra o sarampo foram considerados falsos positivos em pessoas com evidência de outras infecções virais. Resultados: Entre as 463 pessoas com doenças febris exantemáticas que testaram positivo para anticorpos IgM contra o sarampo durante o período, 297 (64 por cento) pessoas foram classificadas como expostas à vacina. Entre os 166 casos não expostos à vacina, 109 (66 por cento) foram considerados falsos positivos baseado na ausência de soroconversão, dos quais 21 (13 por cento) tiveram evidência de infecção por vírus da rubéola, 49 (30 por cento) parvovírus B19 e 28 (17 por cento) infecção por herpes vírus humano 6. Conclusões: Após a interrupção da transmissão do vírus do sarampo é necessária exaustiva investigação dos casos com IgM reagente contra o sarampo, especialmente dos casos não expostos à vacina. Testes laboratoriais para etiologias das doenças febris exantemáticas ajudam na interpretação destes casos

The expression of genes coding for distinct types of glycine-rich proteins varies according to the biology of three metastriate ticks, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus and Amblyomma cajennense

Background: Ticks secrete a cement cone composed of many salivary proteins, some of which are rich in the amino acid glycine in order to attach to their hosts' skin. Glycine-rich proteins (GRPs) are a large family of heterogeneous proteins that have different functions and features; noteworthy are their adhesive and tensile characteristics. These properties may be essential for successful attachment of the metastriate ticks to the host and the prolonged feeding necessary for engorgement. In this work, we analyzed Expressed Sequence Tags (ESTs) similar to GRPs from cDNA libraries constructed from salivary glands of adult female ticks representing three hard, metastriate species in order to verify if their expression correlated with biological differences such as the numbers of hosts ticks feed on during their parasitic life cycle, whether one (monoxenous parasite) or two or more (heteroxenous parasite), and the anatomy of their mouthparts, whether short (Brevirostrata) or long (Longirostrata). These ticks were the monoxenous Brevirostrata tick, Rhipicephalus (Boophilus) microplus, a heteroxenous Brevirostrata tick, Rhipicephalus sanguineus, and a heteroxenous Longirostrata tick, Amblyomma cajennense. To further investigate this relationship, we conducted phylogenetic analyses using sequences of GRPs from these ticks as well as from other species of Brevirostrata and Longirostrata ticks. Results: cDNA libraries from salivary glands of the monoxenous tick, R. microplus, contained more contigs of glycine-rich proteins than the two representatives of heteroxenous ticks, R. sanguineus and A. cajennense (33 versus, respectively, 16 and 11). Transcripts of ESTs encoding GRPs were significantly more numerous in the salivary glands of the two Brevirostrata species when compared to the number of transcripts in the Longirostrata tick. The salivary gland libraries from Brevirostrata ticks contained numerous contigs significantly similar to silks of true spiders (17 and 8 in, respectively, R. microplus and R. sanguineus), whereas the Longirostrata tick contained only 4 contigs. The phylogenetic analyses of GRPs from various species of ticks showed that distinct clades encoding proteins with different biochemical properties are represented among species according to their biology. Conclusions: We found that different species of ticks rely on different types and amounts of GRPs in order to attach and feed on their hosts. Metastriate ticks with short mouthparts express more transcripts of GRPs than a tick with long mouthparts and the tick that feeds on a single host during its life cycle contain a greater variety of these proteins than ticks that feed on several hosts.

Identification of a Highly Antigenic Linear B Cell Epitope within Plasmodium vivax Apical Membrane Antigen 1 (AMA-1)

Apical membrane antigen 1 (AMA-1) is considered to be a major candidate antigen for a malaria vaccine. Previous immunoepidemiological studies of naturally acquired immunity to Plasmodium vivax AMA-1 (PvAMA-1) have shown a higher prevalence of specific antibodies to domain II (DII) of AMA-1. In the present study, we confirmed that specific antibody responses from naturally infected individuals were highly reactive to both full-length AMA-1 and DII. Also, we demonstrated a strong association between AMA-1 and DII IgG and IgG subclass responses. We analyzed the primary sequence of PvAMA-1 for B cell linear epitopes co-occurring with intrinsically unstructured/ disordered regions (IURs). The B cell epitope comprising the amino acid sequence 290-307 of PvAMA-1 (SASDQPTQYEEEMTDYQK), with the highest prediction scores, was identified in domain II and further selected for chemical synthesis and immunological testing. The antigenicity of the synthetic peptide was identified by serological analysis using sera from P. vivax-infected individuals who were knowingly reactive to the PvAMA-1 ectodomain only, domain II only, or reactive to both antigens. Although the synthetic peptide was recognized by all serum samples specific to domain II, serum with reactivity only to the full-length protein presented 58.3% positivity. Moreover, IgG reactivity against PvAMA-1 and domain II after depletion of specific synthetic peptide antibodies was reduced by 18% and 33% (P = 0.0001 for both), respectively. These results suggest that the linear epitope SASDQPTQYEEEMTDYQK is highly antigenic during natural human infections and is an important antigenic region of the domain II of PvAMA-1, suggesting its possible future use in pre-clinical studies.

Adaptive Immunity against Leishmania Nucleoside Hydrolase Maps Its C-Terminal Domain as the Target of the CD4+ T Cell-Driven Protective Response

Nucleoside hydrolases (NHs) show homology among parasite protozoa, fungi and bacteria. They are vital protagonists in the establishment of early infection and, therefore, are excellent candidates for the pathogen recognition by adaptive immune responses. Immune protection against NHs would prevent disease at the early infection of several pathogens. We have identified the domain of the NH of L. donovani (NH36) responsible for its immunogenicity and protective efficacy against murine visceral leishmaniasis (VL). Using recombinant generated peptides covering the whole NH36 sequence and saponin we demonstrate that protection against L. chagasi is related to its C-terminal domain (amino-acids 199-314) and is mediated mainly by a CD4+ T cell driven response with a lower contribution of CD8+ T cells. Immunization with this peptide exceeds in 36.73 +/- 12.33% the protective response induced by the cognate NH36 protein. Increases in IgM, IgG2a, IgG1 and IgG2b antibodies, CD4+ T cell proportions, IFN-gamma secretion, ratios of IFN-gamma/IL-10 producing CD4+ and CD8+ T cells and percents of antibody binding inhibition by synthetic predicted epitopes were detected in F3 vaccinated mice. The increases in DTH and in ratios of TNF alpha/IL-10 CD4+ producing cells were however the strong correlates of protection which was confirmed by in vivo depletion with monoclonal antibodies, algorithm predicted CD4 and CD8 epitopes and a pronounced decrease in parasite load (90.5-88.23%; p = 0.011) that was long-lasting. No decrease in parasite load was detected after vaccination with the N-domain of NH36, in spite of the induction of IFN-gamma/IL-10 expression by CD4+ T cells after challenge. Both peptides reduced the size of footpad lesions, but only the C-domain reduced the parasite load of mice challenged with L. amazonensis. The identification of the target of the immune response to NH36 represents a basis for the rationale development of a bivalent vaccine against leishmaniasis and for multivalent vaccines against NHs-dependent pathogens.

Plasmodium vivax circumsporozoite genotypes: a limited variation or new subspecies with major biological consequences?

Background: Plasmodium vivax circumsporozoite variants have been identified in several geographical areas. The real implication of the genetic variation in this region of the P. vivax genome has been questioned for a long time. Although previous studies have observed significant association between VK210 and the Duffy blood group, we present here that evidences of this variation are limited to the CSP central portion. Methods: The phylogenetic analyses were accomplished starting from the amplification of conserved domains of 18 SSU RNAr and Cyt B. The antibodies responses against the CSP peptides, MSP-1, AMA-1 and DBP were detected by ELISA, in plasma samples of individuals infected with two P. vivax CS genotypes: VK210 and P. vivax-like. Results: These analyses of the two markers demonstrate high similarity among the P. vivax CS genotypes and surprisingly showed diversity equal to zero between VK210 and P. vivax-like, positioning these CS genotypes in the same clade. A high frequency IgG antibody against the N- and C-terminal regions of the P. vivax CSP was found as compared to the immune response to the R- and V-repetitive regions (p = 0.0005, Fisher's Exact test). This difference was more pronounced when the P. vivax-like variant was present in the infection (p = 0.003, Fisher's Exact test). A high frequency of antibody response against MSP-1 and AMA-1 peptides was observed for all P. vivax CS genotypes in comparison to the same frequency for DBP. Conclusions: This results target that the differences among the P. vivax CS variants are restrict to the central repeated region of the protein, mostly nucleotide variation with important serological consequences.

Unexpected Diversity of Cellular Immune Responses against Nef and Vif in HIV-1-Infected Patients Who Spontaneously Control Viral Replication

Background: HIV-1-infected individuals who spontaneously control viral replication represent an example of successful containment of the AIDS virus. Understanding the anti-viral immune responses in these individuals may help in vaccine design. However, immune responses against HIV-1 are normally analyzed using HIV-1 consensus B 15-mers that overlap by 11 amino acids. Unfortunately, this method may underestimate the real breadth of the cellular immune responses against the autologous sequence of the infecting virus. Methodology and Principal Findings: Here we compared cellular immune responses against nef and vif-encoded consensus B 15-mer peptides to responses against HLA class I-predicted minimal optimal epitopes from consensus B and autologous sequences in six patients who have controlled HIV-1 replication. Interestingly, our analysis revealed that three of our patients had broader cellular immune responses against HLA class I-predicted minimal optimal epitopes from either autologous viruses or from the HIV-1 consensus B sequence, when compared to responses against the 15-mer HIV-1 type B consensus peptides. Conclusion and Significance: This suggests that the cellular immune responses against HIV-1 in controller patients may be broader than we had previously anticipated.