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Low incidence and high population viral suppression in Malawi: the Chiradzulu HIV Incidence Study
David Maman, Sophie Masson, Benson Chilema, Charles Masiku, Elizabeth Szumilin, Ahidjo Ayouba, Benjamin Riche, Etard Jean-Francois *Clinical research Department, Epicentre, Paris, France, Community Health Science Unit, Ministry of Health, Lilongwe, Malawi, Medecins sans Frontieres, Lilongwe, Malawi, Medecins sans Frontieres, Paris, France, UMI , Institut de Recherche pour le developpement, Montpellier, France, Biostatistic Unit, Hospices Civils de Lyon, Lyon, France,Umi 233 , Institut de Recherche pour le Developpement, Montpellier, France
Background: The rural district of Chiradzulu, in Malawi, was the site of the first antiretroviral (ART) program implemented in sub-Saharan Africa by Medecins Sans Frontieres (MSF) together with the Ministry of Health. ART became available there in early 2001, decentralization of care was completed in 2003, and task shifting allowing nurses to initiate ART started in 2006. By the end of June 2013, 27,000 patients (within a district of 280,000 inhabitants in total) were receiving ART. Here we present findings of the Chiradzulu HIV Impact in Population Study (CHIPS), which directly measured HIV Incidence, population viral load and coverage at each step within the cascade of care in early 2013, after 15 years of a district-wide program. This is one of the first population-level studies incorporating these specific metrics, which WHO recently identified as the most relevant for evaluating and optimizing both the therapeutic benefit of HIV treatment to individuals and the public health effectiveness of “treatment as prevention” strategies. Methodology: Cross-sectional population-based survey . The study was conducted between February and May 2013. Using a multistage cluster sampling method, we recruited all individuals age 15 to 59 living in 4,125 selected households. Each individual who agreed to participate was interviewed and tested for HIV at home. All participants who tested positive also had their CD4 count and viral load measured. The Lag and Biorad Avidity assays were used to distinguish recent from long-term infection. Results: Of 8,271 individuals eligible for the study 7,269 agreed to participate and were tested for HIV (94.1% inclusion for women and 80.3% for men). Overall HIV prevalence was 17.0% (95%CI 16.1 - 17.8). Based on the LAg and Biorad avidity assays results, overall incidence was 0.39 (95%CI 0.0-0.77) and 0.34 (95%CI 0-0.72) new cases per 100 Person-Years respectively. Incidence was higher among women compared to men (0.57 vs 0.18 new cases per 100PY Coverage at steps along the HIV care cascade was found to be as follows. Among the total HIV-infected population, 76.7% (95%CI 74.4 - 79.1) had been previously diagnosed, 71.2% (95%CI 68.6-73.6) were in care, 65.8% (95%CI 62.8-68.2) were on ART and 61.8% (95%CI 59.0-64.5) had a viral load below 1,000 copies. Proportion of population viral suppression (VL<1,000copies/ml) was higher in women compare with men (65.3% vs 53.9%, p<0.001) Conclusions: This population incidence study suggests that high levels of population viral suppression and low incidence can be achieved in highprevalence settings in sub-Saharan Africa. However, no causal relation between population viral suppression and low incidence can be made from this cross-sectional study.