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Objective: To identify the incidence of and risk factors for tuberculosis in people living with HIV (PLHIV)., Design: Observational, prospective cohort study., Methods: A total of 2069 HIV-infected patients was observed between July 2007 and December 2010. The Kaplan-Meier method was used to estimate the probability of survival free of tuberculosis, and Cox regression analysis to identify risk factors associated with the development of tuberculosis., Results: Survival free of tuberculosis (TB) was 91%. The incidence rate of tuberculosis was 2.8 per 100 persons/years. Incidence of tuberculosis was higher when subjects had CD4 cell count <200 cells/mm(3); were not on antiretroviral therapy; in those who had, a body mass index <18.5 kg/m(2), anemia (or were not tested for it), were illiterate or referred previous tuberculosis treatment at entry into the cohort. Those not treated for latent TB infection had a much higher risk (HR = 7.9) of tuberculosis than those with a negative tuberculin skin test (TST). Having a TST≥5 mm but not being treated for latent TB infection increased the risk of incident tuberculosis even in those with a history of previous tuberculosis., Conclusions: Preventive actions to reduce the risk of TB in people living with HIV should include an appropriate HAART and treatment for latent TB infection in those with TST≥5 mm. The actions towards enabling rigorous implementation of treatment of latent TB infection and targeting of PLHIV drug users both at the individual and in public health level can reduce substantially the incidence of TB in PLHIV.

Background: In most case control studies the hardest decision is the choice of the control group, as in the ideal control group the proportion exposed is the same as in the population that produced the cases., Methods: A comparison of two control groups in a case control study of the efficacy of BCG revaccination. One group was selected from subjects presenting to the heath unit the case attended for routine prevention and care; the second group was selected from the neighbourhood of cases. All Health Units from which controls were selected offered BCG revaccination. Efficacy estimated in a randomized control trial of BCG revaccination was used to establish that the neighbourhood control group was the one that gave unbiased results., Results: The proportion of controls with scars indicating BCG revaccination was higher among the control group selected from Health Unit attenders than among neighbourhood controls. This excess was not removed after control for social variables and history of exposure to tuberculosis, and appears to have resulted from the fact that people attending the Health Unit were more likely to have been revaccinated than neighbourhood controls, although we can not exclude an effect of other unmeasured variables., Conclusion: In this study, controls selected from people presenting to a Health Unit overrepresented exposure to BCG revaccination. Had the results from the HU attenders control group been accepted this would have resulted in overestimation of vaccine efficacy. When the exposure of interest is offered in a health facility, selection of controls from attenders at the facility may result in over representation of exposure in controls and selection bias.

Setting: Metropolitan region of Recife, Brazil., Objective: To estimate the additional protection against tuberculosis (TB) provided by a second dose of bacille Calmette-Guérin (BCG) vaccine., Design: Case-control study. Cases were cases of TB newly diagnosed by the TB control programme, independent of clinical form. Three matched neighbourhood controls were selected using a systematic routine, starting from the case's address. The matching was within the age groups 7-9, 10-14 and 15-19 years., Results: Analysis was conducted among 169 cases and 477 controls. For the efficacy of BCG revaccination against TB overall, matched (crude) vaccine effectiveness (VE) was -3 (95% CI -50-29) and matched (adjusted) VE was 8 (95% CI -77-52)., Conclusions: This study suggests that a second dose of BCG does not offer additional protection. Revaccination should not be offered. As large numbers of subjects are already vaccinated and vaccine appears to offer some protection in older subjects, further studies with larger sample sizes could investigate the potential efficacy of revaccination with BCG in the age group > or = 15 years.