ABSTRACT
O objetivo deste estudo foi de estimar a efetividade das vacinas anti-VHB em um estudo longitudinal, retrospectivo composto por 1.012 doadores de sangue que completaram o esquema padrão de vacinação (três doses, incluindo doses de reforço nos doadores com títulos de anti-HBs <10UI/L) durante o período entre 1998 e 2002. Os resultados mostram que a taxa de soroconversão foi significativamente menor nos doadores cujo título de anti-HBs foi mensurado após seis meses decorridos do término do esquema de vacinação e nos doadores com mais de 50 anos. A efetividade média correspondeu a 88,7 por cento, variando de 80,6 por cento nos com maior idade (50 anos ou mais) a 91,4 por cento nos doadores mais jovens (18 a 30 anos). O regime de dose de reforço foi efetivo, principalmente por reduzir o percentual de não-respondedores. Conclui-se que a efetividade da vacina foi significativamente maior nos doadores mais jovens e que o tempo decorrido entre a vacinação e a testagem interferiu na taxa de soroconversão.
The objective of this work was to estimate the effectiveness of DNA recombinant anti-HBV vaccines in a retrospective cohort study of 1,012 Brazilian blood donors who completed the vaccination schedule (3 doses + booster of antibody titer <10IU/L) during the period 1998-2002. The results showed that seroconversion rates were significantly lower among the donors whose antibody titers was measured six months after completing the vaccination scheme and among older donors, particularly those aged over 50. Overall vaccine effectiveness was 88.7 percent, ranging from 80.6 percent in the oldest (50 years or over) to 91.4 percent among the youngest (18-30 years) donors. The booster regimen was effective at reducing the percentage of non-responders. We conclude that vaccine effectiveness was significantly better in younger blood donors and that the anti-HBs testing interval influenced the vaccine effectiveness.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Blood Donors , Hepatitis B Antibodies/blood , Hepatitis B Vaccines/administration & dosage , Hepatitis B/prevention & control , Vaccines, DNA/administration & dosage , Age Factors , Brazil , Hepatitis B Vaccines/immunology , Hepatitis B/immunology , Immunization Schedule , Logistic Models , Longitudinal Studies , Multivariate Analysis , Reproducibility of Results , Retrospective Studies , Vaccines, DNA/immunologyABSTRACT
The objective of this study was to establish the time trend in HIV seroprevalence among blood donors to a large blood bank in southern Brazil during the decade of 1990, and compare it to other data sources from the same region. To this end, a retrospective study of blood donors records in HEMOSC (Center of Hemotherapy of Santa Catarina), federal state of Santa Catarina, Brazil, was conducted for the period 1991 through 1999. Annual seroprevalence of HIV among blood donors and its time trend for the entire period were calculated. The HIV seropositive fraction doubled every 3 years, reaching 4 news cases per 1,000 donors per year by the end of the decade, or roughly twice the national average. The increase occurred particularly among female blood donors, those over 46 years of age, and those residing in the Florianópolis metropolitan area. We conclude that, in the decade of 1990, the frequence of HIV in southern Brazil increased in the population seeking to donate blood. Possible reasons for this increase include an increased use of blood donation as a means to obtain HIV testing or increased transmission among low risk populations. The effect of increased transfusion risk of HIV transmission requires urgent attention.