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Browsing by Issue Date, starting with "2012-01-05"

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  • Antibody response to the influenza vaccine in healthcare workers
    Publication . Sacadura-Leite, Ema; Sousa-Uva, António; Rebelo-de-Andrade, Helena
    People vaccinated against influenza develop hemagglutination inhibition (HAI) antibodies (Ab) that bind to the virus and neutralize it. Ab titer levels are variable depending on factors insufficiently studied, and tend to decrease over time. In the present study, we analyzed antibodies responses before and after influenza vaccination in nurses working in a hospital, with the aim of: -identifying seroconversion rates to trivalent influenza vaccine one month after immunization; -evaluating if, six months after vaccination, influenza HAI Ab titer fall comparing to one-month post vaccination HAI Ab titer; -studying the association between the lack of HAI Ab response (seroconversion) assessed one month after immunization and: ∘past influenza vaccinations, ∘baseline (before vaccination) HAI Ab titer, ∘baseline (before vaccination) HAI Ab titer ≥ 40 (considered as a protection titer). Hemagglutination inhibition reaction was used to assess specific HAI Ab titers against influenza A(H1N1), A(H3N2) and B virus strains included in the influenza vaccine and we used progressive dilutions of two times, starting on 1:10 until 1:20.480. Seroconversion rates, one month after vaccination, were 66.7% for A(H1N1) strain, 63.2% for A(H3N2) strain and 56.3% for B strain. The most immunogenic strain used in 2007/08 influenza vaccine was A(H1N1). Seroconversion rates after one month were negatively associated with past influenza vaccinations, baseline HAI Ab titers ≥ 40 and baseline HAI Ab titers. Six months after vaccination, 50% of participants showed a drop in HAI Ab titers to an half, for each of the considered strains, but they remain high enough to protect against the disease.
    2012-01-05Journal article Restricted access Show more
  • Bridging the gap between PCR detection of Mycobacterium tuberculosis complex and tuberculosis diagnosis
    Publication . Duarte, E. L.; Paixão, E.; David, S.
    The growing demand for rapid diagnosis of tuberculosis (TB) has led to the incorporation of nucleic acid amplification (NAA) tests in case definitions. The objective of this study was to evaluate the contribution of a real-time polymerase chain reaction (PCR) assay in providing a result predictive of a confirmed TB case. Respiratory and extra-pulmonary specimens (n = 308) were subjected to NAA, culture and smear microscopy. Qualitative PCR assessment, translated by an increase in NAA cycles, disregarding template copy number, resulted in an increase in confirmed cases, helping to bridge the gap between the test’s analytical performance and its actual performance in TB diagnosis.
    2012-01-05Journal article Restricted access Show more