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1.  Modelling the Force of Infection for Hepatitis A in an Urban Population-Based Survey: A Comparison of Transmission Patterns in Brazilian Macro-Regions 
PLoS ONE  2014;9(5):e94622.
This study aimed to identify the transmission pattern of hepatitis A (HA) infection based on a primary dataset from the Brazilian National Hepatitis Survey in a pre-vaccination context. The national survey conducted in urban areas disclosed two epidemiological scenarios with low and intermediate HA endemicity.
A catalytic model of HA transmission was built based on a national seroprevalence survey (2005 to 2009). The seroprevalence data from 7,062 individuals aged 5–69 years from all the Brazilian macro-regions were included. We built up three models: fully homogeneous mixing model, with constant contact pattern; the highly assortative model and the highly assortative model with the additional component accounting for contacts with infected food/water. Curves of prevalence, force of infection (FOI) and the number of new infections with 99% confidence intervals (CIs) were compared between the intermediate (North, Northeast, Midwest and Federal District) and low (South and Southeast) endemicity areas. A contour plot was also constructed.
The anti- HAV IgG seroprevalence was 68.8% (95% CI, 64.8%–72.5%) and 33.7% (95% CI, 32.4%–35.1%) for the intermediate and low endemicity areas, respectively, according to the field data analysis. The models showed that a higher force of infection was identified in the 10- to 19-year-old age cohort (∼9,000 infected individuals per year per 100,000 susceptible persons) in the intermediate endemicity area, whereas a higher force of infection occurred in the 15- to 29-year-old age cohort (∼6,000 infected individuals per year per 100,000 susceptible persons) for the other macro-regions.
Our findings support the shift of Brazil toward intermediate and low endemicity levels with the shift of the risk of infection to older age groups. These estimates of HA force of infection stratified by age and endemicity levels are useful information to characterize the pre-vaccination scenario in Brazil.
PMCID: PMC4028178  PMID: 24845598
Despite the effectiveness of combination antiretroviral therapy in the treatment of people living with HIV/AIDS (PLWHA), nonadherence to medication has become a major threat to its effectiveness. This study aimed to estimate the prevalence of self-reported irregular use of antiretroviral therapy and the factors associated with such an irregularity in PLWHA. A cross-sectional study of PLWHA who attended two referral centers in the city of Recife, in Northeastern Brazil, between June 2007 and October 2009 was carried out. The study analyzed socioeconomic factors, social service support and personal habits associated with nonadherence to antiretroviral therapy, adjusted by multivariable logistic regression analysis. The prevalence of PLWHA who reported irregular use of combination antiretroviral therapy (cART) was 25.7%. In the final multivariate model, the irregular use of cART was associated with the following variables: being aged less than 40 years (OR = 1.66, 95%-CI: 1.29-2.13), current smokers (OR = 1.76, 95%-CI: 1.31-2.37) or former smokers (OR = 1.43, 95%-CI: 1.05-1.95), and crack cocaine users (OR = 2.79, 95%-CI: 1.24-6.32). Special measures should be directed towards each of the following groups: individuals aged less than 40 years, smokers, former smokers and crack cocaine users. Measures for giving up smoking and crack cocaine should be incorporated into HIV-control programs in order to promote greater adherence to antiretroviral drugs and thus improve the quality of life and prolong life expectancy.
PMCID: PMC4085845  PMID: 24626414
AIDS; Adherence; Antiretroviral therapy; Associated factors
3.  Factors Related to Changes in CD4+ T-Cell Counts over Time in Patients Living with HIV/AIDS: A Multilevel Analysis 
PLoS ONE  2014;9(2):e84276.
The measurement of CD4+ T-cell (CD4) counts is a strong predictor of progression to AIDS and a means of monitoring antiviral therapy (ART). The success or failure of controlling virus levels in untreated patients or those taking ART may be associated with treatment adherence, habits, correlated infections unrelated to HIV, cancer, immunosuppressive drugs; as well as socio-economic and psychosocial aspects and access to healthcare. The aim of the present study was to identify, using a multilevel model, the factors related to the variations of CD4 counts over time, in patients living with HIV.
A cohort study was conducted with patients living with HIV, selected from July 2007 to December 2010. Patients were monitored from records of their first CD4 count after being diagnosed with HIV. A multilevel model with 3 levels of aggregation was applied to analyze the associations of predictor variables and the behavior of CD4 over time.
Principal Findings
A total of 1870 patients were enrolled. The mean number of CD4 at the beginning of the cohort was 393.1 cells/mm3, and there was a mean increase of 1.529 cells/mm3 per month. Patient's age, smoking, use of illicit drugs, hospital treatment, changing doctors and the use of ART, were factors that affected the kinetics of the CD4 count during the follow-up period.
The results of this study indicated increased levels of CD4 over time in a cohort of patients living with HIV/AIDS and identified factors that may influence this increase and are liable to intervention.
PMCID: PMC3914785  PMID: 24505247
4.  Incidence and Risk Factors for Tuberculosis in People Living with HIV: Cohort from HIV Referral Health Centers in Recife, Brazil 
PLoS ONE  2013;8(5):e63916.
To identify the incidence of and risk factors for tuberculosis in people living with HIV (PLHIV).
Observational, prospective cohort study.
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.
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/mm3; were not on antiretroviral therapy; in those who had, a body mass index <18.5 kg/m2, 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.
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.
PMCID: PMC3651200  PMID: 23675515
5.  Associated factors for treatment delay in pulmonary tuberculosis in HIV-infected individuals: a nested case-control study 
BMC Infectious Diseases  2012;12:208.
The delay in initiating treatment for tuberculosis (TB) in HIV-infected individuals may lead to the development of a more severe form of the disease, with higher rates of morbidity, mortality and transmissibility. The aim of the present study was to estimate the time interval between the onset of symptoms and initiating treatment for TB in HIV-infected individuals, and to identify the factors associated to this delay.
A nested case-control study was undertaken within a cohort of HIV-infected individuals, attended at two HIV referral centers, in the state of Pernambuco, Brazil. Delay in initiating treatment for TB was defined as the period of time, in days, which was greater than the median value between the onset of cough and initiating treatment for TB. The study analyzed biological, clinical, socioeconomic, and lifestyle factors as well as those related to HIV and TB infection, potentially associated to delay. The odds ratios were estimated with the respective confidence intervals and p-values.
From a cohort of 2365 HIV-infected adults, 274 presented pulmonary TB and of these, 242 participated in the study. Patients were already attending 2 health services at the time they developed a cough (period range: 1 – 552 days), with a median value of 41 days. Factors associated to delay were: systemic symptoms asthenia, chest pain, use of illicit drugs and sputum smear-negative.
The present study indirectly showed the difficulty of diagnosing TB in HIV-infected individuals and indicated the need for a better assessment of asthenia and chest pain as factors that may be present in co-infected patients. It is also necessary to discuss the role played by negative sputum smear results in diagnosing TB/HIV co-infection as well as the need to assess the best approach for drug users with TB/HIV.
PMCID: PMC3490888  PMID: 22958583
HIV; Tuberculosis; Delay

Results 1-5 (5)