High efficacy of first-line ART in a West African cohort, assessed by dried blood spot virological and pharmacological measurements.

OBJECTIVES: The objectives of this study were to determine the rate of viral success in HIV-infected patients on first-line ART by the assessment of dried blood spot (DBS) viral load (VL) and to assess the performance of DBS sampling for VL measurement, genotypic resistance and antiretroviral concentration determinations. METHODS: HIV-infected patients treated for >1 year with first-line ART in Niamey, Niger were included. VL based on nucleic acid sequence-based amplification (NASBA) assay (limit of quantification <800 copies/mL) was measured on DBS capillary samples. Resistance genotype was assessed for all detectable VLs (limit of detection >100 copies/mL); antiretroviral concentrations were interpreted using standard plasma cut-offs after extrapolation of blood to plasma results. Median (IQR) results are presented. RESULTS: Two hundred and eighteen patients (61% women), aged 41 (34-46) years, with 138 (56-235) CD4 cells/mm3 at baseline were included. After 4 (2-6) years of follow-up under therapy, CD4 gain was +197 (98-372) cells/mm3; 81% had VL <800 copies/mL. Antiretroviral concentrations were adequate in 87% of patients and nevirapine/efavirenz concentrations were related to viral success (P < 0.001). DBS genotypic resistance amplification succeeded in 71% of failing patients: NRTI drug resistance mutations were identified in 73% including resistance to lamivudine/emtricitabine (67%), abacavir (30%) and tenofovir (21%); and NNRTI drug resistance mutations were identified in 82% including resistance to rilpivirine (39%) and etravirine (15%). CONCLUSIONS: This study demonstrated a good response after 4 years of first-line ART in Niger. Adherence was high, according to antiretroviral concentrations, and the majority of failures were explained by selection of drug resistance mutations detected in the DBS genotype. Using DBS might improve the assessment of ART failure in HIV-infected patients in low-income countries.

Molecular characterization of hepatitis B virus from chronically-infected patients in Niamey, Niger.

OBJECTIVES: In Niger, 65% of hepatocarcinoma and 75% of cirrhosis cases were due to hepatitis B virus (HBV). We studied the genotypic characteristics of HBsAg in chronically HBV-infected patients in Niamey. METHODS: We studied prospectively HBV genotypic patterns among hospitalized patients with HBV infection in the National Hospital of Niamey, Niger. Patients were screened for hepatitis B surface antigen (HBsAg) and HBV genotyping was performed on the HBsAg-positive patients. RESULTS: In this study, we have confirmed the predominance of the HBV genotype E (HBV-E) in Niger and have identified 2 recombinant forms including HBV-E/D and HBV-A3/E reported previously among blood donors in Niger and Ghana, respectively. Amino acid substitutions found in HBV sequences obtained here included P120T, S143L, G145A and A194T. These substitutions were characterized as being associated with modified antigenicity and, notably, with impaired serological detection of HBsAg, while the A194T variant was found to have a controversial role in reduced susceptibility to tenofovir. CONCLUSIONS: We have identified two recombinant HBV forms and rare genotypic patterns in Niger that may affect hepatitis B surface antigen antigenicity, and improve current knowledge of epidemiological, clinical and virological patterns of hepatitis B in this country.

Is universal HBV vaccination of healthcare workers a relevant strategy in developing endemic countries? The case of a university hospital in Niger.

BACKGROUND: Exposure to hepatitis B virus (HBV) remains a serious risk to healthcare workers (HCWs) in endemic developing countries owing to the strong prevalence of HBV in the general and hospital populations, and to the high rate of occupational blood exposure. Routine HBV vaccination programs targeted to high-risk groups and especially to HCWs are generally considered as a key element of prevention strategies. However, the high rate of natural immunization among adults in such countries where most infections occur perinatally or during early childhood must be taken into account. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a cross sectional study in 207 personnel of 4 occupational groups (medical, paramedical, cleaning staff, and administrative) in Niamey's National Hospital, Niger, in order to assess the prevalence of HBV markers, to evaluate susceptibility to HBV infection, and to identify personnel who might benefit from vaccination. The proportion of those who declared a history of occupational blood exposure ranged from 18.9% in the administrative staff to 46.9% in paramedical staff. Only 7.2% had a history of vaccination against HBV with at least 3 injections. Ninety two percent were anti-HBc positive. When we focused on170 HCWs, only 12 (7.1%) showed no biological HBV contact. Twenty six were HBsAg positive (15,3%; 95% confidence interval: 9.9%-20.7%) of whom 8 (32%) had a viral load >2000 IU/ml. CONCLUSIONS/SIGNIFICANCE: The very small proportion of HCWs susceptible to HBV infection in our study and other studies suggests that in a global approach to prevent occupational infection by bloodborne pathogens, a universal hepatitis B vaccination of HCWs is not priority in these settings. The greatest impact on the risk will most likely be achieved by focusing efforts on primary prevention strategies to reduce occupational blood exposure. HBV screening in HCWs and treatment of those with chronic HBV infection should be however considered.