The prevalence of antibodies to hepatitis A and B virus was assessed in 3,653 subjects across four regions of Brazil. The anti-HAV and anti-HBc seroprevalence were 64.7% and 7.9%, respectively. The highest anti-HAV (92.8%) and anti-HBc (21.4%) rates were seen in the Northern region. In other regions, anti-HAV seroprevalence over 90% was only reached in the more elderly, indicating an intermediate endemicity and a significantly higher anti-HAV prevalence was seen in the low socioeconomic group between 1-30 years. With respect to anti-HBc seroprevalence an increase was seen in adolescents and there was a significantly higher anti-HBc prevalence in the lower socioeconomic group between 1-20 years. A 3.1% anti-HBc prevalence was seen in one-year-old infants, suggesting a vertical transmission. The major findings of this study indicate that the pre-adolescent and adolescent population in some Brazilian cities are at greatest risk from both hepatitis A and B infection, but for different reasons.

The seroprevalence of hepatitis B was investigated in over 12,000 subjects in six countries of Latin America: Argentina, Brazil, Chile, the Dominican Republic, Mexico, and Venezuela. Each study population was stratified according to age, gender, and socioeconomic status. Antibodies against hepatitis B core antigen (anti-HBc) were measured in order to determine hepatitis B infection. The highest overall seroprevalence was found in the Dominican Republic (21.4%), followed by Brazil (7.9%), Venezuela (3.2%), Argentina (2.1%), Mexico (1.4%), and Chile (0.6%). In all the countries an increase in seroprevalence was found among persons 16 years old and older, suggesting sexual transmission as the major route of infection. In addition, comparatively high seroprevalence levels were seen at an early age in the Dominican Republic and Brazil, implicating a vertical route of transmission.

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ResumoObjetivos: A varicela tem conseqüências mais graves em adolescentes e adultos. Recentes relatos da Europa e da Ásia mostram um número crescente de adolescentes e adultos jovens soronegativos. Como são poucos os dados sobre a prevalência de anti-VZV no Brasil e com o objetivo de definir estratégias para a imunização contra a varicela, realizamos um estudo de soroprevalência para o VZV (vírus varicela zoster) em diferentes partes do Brasil.Métodos: Este estudo soroepidemiológico, transversal e populacional foi realizado em quatro diferentes regiões do Brasil. A população estudada foi estratificada por sexo, idade e situação socioeconômica. Anticorpos Ig G, anti-VZV foram analisados pelo método ELISA.Resultados: Foram incluídos no estudo 3.879 indivíduos de 1 a 40 anos. A taxa de soropositividade do anti-VZV em todos os grupos etários e centros no Brasil foi de 85,4 %. Evidenciou-se uma forte correlação com a idade. Especialmente no Sudeste e Sul, a soroprevalência foi menor no grupo etário de 1-5 anos (44,5% e 57,8%, respectivamente). Na região Norte esta taxa foi de 88,9%. No geral, a infecção pelo VZV foi independente do nível socioeconômico, entretanto nos grupos etários jovens (1-10 anos) a soroprevalência foi significativamente menor nas classes alta/média, na maioria das regiões. A história clínica de varicela se correlacionou com a soropositividade anti-VZV, tendo um valor preditivo de 95,1%.Conclusões: Na pré-adolescência, uma proporção substancial da população brasileira é susceptível à varicela e uma parcela considerável de adolescentes e adultos jovens permanecem soronegativos e, conseqüentemente, em risco. AbstractObjectives: Varicella has more serious consequences in adolescents and adults. Recent reports from Europe and Asia show an increasing number of adolescents and young adults being seronegative. As there is only limited data on varicella zoster virus (VZV) seroprevalence in Brazil and to facilitate the strategy for varicella vaccination we conducted a VZV seroprevalence study in Brazil.Methods: This population-based, cross sectional seroepidemiology study was performed in 4 different regions of Brazil. The studied population was stratified according to gender, age and socioeconomic status. VZV IgG antibodies were analyzed by ELISA.Results: 3,879 subjects aged 1-40 years were included into the study. The overall anti-VZV seropositivity rate across all age groups and centers in Brazil was 85.4%. There was a strong age relationship. Especially in the South East and South seroprevalence was low in the age group 1-5 years (44.5% and 57.8%, respectively) while in the North the rate was 88.9%. Overall, Varicella infection was independent of the socioeconomic level, but in the youngest age groups (1-10 years) seroprevalence rates were significantly lower in the high/medium socioeconomic class for most regions. Clinical history of chickenpox correlates well with anti-VZV seropositivity with a predictive value of 95.1%Conclusions: In preadolescence a substantial proportion of the Brazilian populat...