RESUMO
Serum responses to oral cholera vaccines were assessed in three paediatric vaccine trials, two in León, Nicaragua and one in Stockholm, Sweden. A calibrated anti-cholera toxin B subunit (CTB) IgA ELISA was used together with an assay for vibriocidal antibodies. Swedish children had lower pre-vaccination levels of antibody, but serum responses were more pronounced in Swedish children than in Nicaraguan children. Post-vaccination levels of anti-toxin antibody were generally above those found after natural infections with enterotoxigenic Escherichia coli, that cross-reacts serologically with Vibrio cholerae. Adverse events seen after vaccination were generally mild and of little clinical significance.
Assuntos
Anticorpos Antibacterianos/biossíntese , Vacinas contra Cólera/imunologia , Vacinação , Vacinas de Produtos Inativados/imunologia , Vibrio cholerae/imunologia , Administração Oral , Calibragem , Criança , Pré-Escolar , Vacinas contra Cólera/administração & dosagem , Ensaios Clínicos como Assunto , Método Duplo-Cego , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lactente , Masculino , Nicarágua , Segurança , Testes Sorológicos , Suécia , Vacinas de Produtos Inativados/administração & dosagemRESUMO
Diarrheal episodes with enterotoxigenic Escherichia coli (ETEC) were prospectively monitored during the first 2 years of life in a cohort of 235 infants from Leon, Nicaragua. ETEC was an etiological finding in 38% (310 of 808) of diarrheal episodes and in 19% (277 of 1,472) of samples taken as asymptomatic controls at defined age intervals (P = <0.0001). The majority of diarrheal episodes (80%) occurred before 12 months of age. The major ETEC type was characterized by colonization factor CFA I and elaboration of both heat-labile enterotoxin and heat-stable enterotoxin (ST). The proportion of E. coli strains with CFA I was significantly higher in cases with diarrhea (P = 0.002). The second most prevalent type showed putative colonization factor PCFO166 and production of ST. The prevalence of PCFO166 was approximately 20%, higher than reported before. Children with a first CFA I episode contracted a second ETEC CFA I infection 24% of the time, compared with 46% for ETEC strains of any subtype. Most of the ETEC episodes were of moderate severity, and only 5% (15 of 310) were characterized as severe. In conclusion, our results give valuable information for the planning of intervention studies using ETEC vaccines.