Prevalence of hepatitis B virus infection and its associated factors among students in N'Djamena, Chad.

INTRODUCTION: Infection by hepatitis B virus (HBV) is a major issue in public health. The prevalence of HBV in Chad is 12.4%, all age groups considered. Here, we aimed to determine the prevalence of HBV and its associated factors among university students in N'Djamena, the country's capital. METHODS: A cross-sectional survey of students at either the University of N'djamena or Emi Koussi University was conducted from 3 to 23 July 2021. All participating students provided signed, informed consent and were included in the study consecutively. Blood samples were collected, and serum tested for hepatitis B surface antigen (HBsAg) using the Determine HBsAg rapid test kit, with confirmation of positive tests on an Abbott Architect i1000SR analyzer. Descriptive analysis and logistic regression were used to determine associations between the outcome variable and independent/covariate variables. RESULTS: A total of 457 students with a median age of 24 years were included across different faculties. The prevalence of HBV infection was 14.87% (68/457). Most students (75%) were aged 25 years or less. Unprotected sex was reported by 64.9% of the students and multiple sexual partners by 53.6%. Furthermore, 45.7% of them reported having no knowledge of hepatitis B. Having an HBsAg-positive mother (AOR: 2.11), having a history of transcutaneous medical procedures (AOR: 2.97) and living with a family (AOR: 4.63) were significantly associated with HBV status. Age ≥26 years appeared as a protective factor (AOR = 0.41). CONCLUSION: Our study detected a high, 14.87% prevalence of HBV infection among students in N'djamena, Chad, and shed light on its associated factors. HBV prevention strategies should include raising awareness among students, making full hepatitis vaccination mandatory before children begin school, promoting mass screening to identify and treat chronic HBV carriers and reduce transmission, and reducing the cost of vaccination.

Heterogeneity of the Omicron variant in Senegal.

•Omicron variant continues to progress in Senegal with the appearance of new contaminations.•IRESSEF detected the first positive case of the Omicron variant on Friday, December 3, 2021.•Since this date, the number of Omicron variant infections has increased over the weeks.•Molecular surveillance of the Omicron variant allowed us to identify a strong variation of this variant in our country.

The early SARS-CoV-2 epidemic in Senegal was driven by the local emergence of B.1.416 and the introduction of B.1.1.420 from Europe.

Molecular surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is growing in west Africa, especially in the Republic of Senegal. Here, we present a molecular epidemiology study of the early waves of SARS-CoV-2 infections in this country based on Bayesian phylogeographic approaches. Whereas the first wave in mid-2020 was characterized by a significant diversification of lineages and predominance of B.1.416, the second wave in late 2020 was composed primarily of B.1.1.420. Our results indicate that B.1.416 originated in Senegal and was exported mainly to Europe. In contrast, B.1.1.420 was introduced from Italy, gained fitness in Senegal, and then spread worldwide. Since both B.1.416 and B.1.1.420 lineages carry several positive selected mutations in the spike and nucleocapsid genes, each of which may explain their local dominance, their mutation profiles should be carefully monitored. As the pandemic continues to evolve, molecular surveillance in all regions of Africa will play a key role in stemming its spread.

Model-based cost-effectiveness estimates of testing strategies for diagnosing hepatitis C virus infection in people who use injecting drugs in Senegal.

BACKGROUND: Scaling-up the access to hepatitis C virus (HCV) diagnostics for people who use injecting drugs (PWID) is essential to reduce the HCV incidence in low and middle-income countries. METHODS: A decision tree model was developed to compare the cost-effectiveness of 12 strategies for diagnosing HCV in Senegal with a health sector perspective. Strategies included HCV-Ab screening and confirmation of viraemia (based on HCV-RNA or HCV core antigen detection) or only the latter step. Laboratory assays and decentralized tools (point-of-care (POC) tests and dried blood spot (DBS) samples) were included. The base-case assumed a 38.9% seroprevalence, as reported in the PWID population of Dakar. RESULTS: Compared to the cheapest strategy (POC HCV-Ab followed by POC HCV-RNA (S5)), one strategy remained un-dominated in the base-case: POC HCV-Ab followed by venepuncture-based laboratory HCV-RNA (S3). Above a lost to follow-up testing rate of 2.3%, combining POC HCV-Ab with HCV-RNA on DBS (S4) became more cost-effective than S3. Above this threshold, a single-step POC HCV-RNA (S12) was also found un-dominated (ICER to S5=€3,297.50). S5, S12 and S4 cost €14.21, €17.03 and €36.55/screened individual. Incremental cost-effectiveness ratios (€/additional true positive case) were 2,164.82 (S12 versus S5) and 3,297.50 (S4 versus S12). Whenever HCV seroprevalence reached 55.5%, S12 became more cost-effective than S5. Moreover, S4 required a budget 2 to 2.5 times higher than S5 or S12 for diagnosing 90% of HCV-infected PWID in Dakar. CONCLUSION: A two-step POC-based strategy (S5) would be the most cost-effective option among those proposed in this study for diagnosing HCV in PWID in Senegal. This study illustrates how the lack of secure financing and of data on PWID in LMICs, render difficult to identify the most sustainable strategy in those countries, as well as its implementation.

Hepatitis B virus (HBV) infection amongst children in Senegal: current prevalence and seroprotection level.

INTRODUCTION: Hepatitis B virus (HBV) infection is highly endemic in Senegal. HBV vaccine of all children has been introduced in 1999 and included in the Expanded Programme on Immunization in 2004. The aim of this study was to assess the HBV prevalence and immunity status against HBV amongst children in Senegal. METHODS: Between March and August 2016, consecutive children aged from 6 months to 16 years old were recruited in outpatient department of three main children hospitals in Senegal. Serum samples were analyzed for HBV serology (HBsAg, HBcAb, HBsAb) using ARCHITECT analyzer. Children with HBsAb levels ≥ 10 IU/l) were considered as seroprotected against HBV. RESULTS: During the study period, 295 children fulfilled the criteria for the study and were further analyzed. Three children were HBsAg positive giving a seroprevalence at 1.1% (95% CI: 0.2-3.3), 12/267 (4.5%, 95% CI=2.3-7.7) had positive HBcAb and 226/295 (76.6%, 71.4-81.3) had positive HBsAb including 191 (77.3%, 71.6-82.4) with isolated HBsAb related to previous active immunization. However only 165 children (56%, CI 50-62) had seroprotective HBsAb levels (HBsAb ≥ 10 UI/L) and 63 (21.4, 16.8-26) had a strong seroprotectiondefined by HBsAb ≥ 100 IU/L. CONCLUSION: Our results suggest that although HBV prevalence has significantly decreased in children in Senegal following a better HBV vaccine coverage, the number of children correctly seroprotected is insufficient (56%). Assessing the levels of HBsAb and providing HBV vaccine boosters should be considered in children in Senegal.

Development, Evaluation, and Implementation of a Pan-African Cancer Research Network: Men of African Descent and Carcinoma of the Prostate.

PURPOSE: Cancer of the prostate (CaP) is the leading cancer among men in sub-Saharan Africa (SSA). A substantial proportion of these men with CaP are diagnosed at late (usually incurable) stages, yet little is known about the etiology of CaP in SSA. METHODS: We established the Men of African Descent and Carcinoma of the Prostate Network, which includes seven SSA centers partnering with five US centers to study the genetics and epidemiology of CaP in SSA. We developed common data elements and instruments, regulatory infrastructure, and biosample collection, processing, and shipping protocols. We tested this infrastructure by collecting epidemiologic, medical record, and genomic data from a total of 311 patients with CaP and 218 matched controls recruited at the seven SSA centers. We extracted genomic DNA from whole blood, buffy coat, or buccal swabs from 265 participants and shipped it to the Center for Inherited Disease Research (Baltimore, MD) and the Centre for Proteomics and Genomics Research (Cape Town, South Africa), where genotypes were generated using the UK Biobank Axiom Array. RESULTS: We used common instruments for data collection and entered data into the shared database. Double-entered data from pilot participants showed a 95% to 98% concordance rate, suggesting that data can be collected, entered, and stored with a high degree of accuracy. Genotypes were obtained from 95% of tested DNA samples (100% from blood-derived DNA samples) with high concordance across laboratories. CONCLUSION: We provide approaches that can produce high-quality epidemiologic and genomic data in multicenter studies of cancer in SSA.

High levels of virological failure with major genotypic resistance mutations in HIV-1-infected children after 5 years of care according to WHO-recommended 1st-line and 2nd-line antiretroviral regimens in the Central African Republic: A cross-sectional study.

A large cohort of 220 HIV-1-infected children (median [range] age: 12 [4-17] years) was cared and followed up in the Central African Republic, including 198 in 1st-line and 22 in 2nd-line antiretroviral regimens. Patients were monitored clinically and biologically for HIV-1 RNA load and drug resistance mutations (DRMs) genotyping. A total of 87 (40%) study children were virological responders and 133 (60%) nonresponders. In children with detectable viral load, the majority (129; 97%) represented a virological failure. In children receiving 1st-line regimens in virological failure for whom genotypic resistance test was available, 45% displayed viruses harboring at least 1 DRM to NNRTI or NRTI, and 26% showed at least 1 major DRM to NNRTI or NRTI; more than half of children in 1st-line regimens were resistant to 1st-generation NNRTI and 24% of the children in 1st-line regimens had a major DRMs to PI. Virological failure and selection of DRMs were both associated with poor adherence. These observations demonstrate high rate of virological failure after 3 to 5 years of 1st-line or 2nd-line antiretroviral treatment, which is generally associated with DRMs and therapeutic failure. Overall, more than half (55%) of children receiving 1st-line antiretroviral treatment for a median of 3.4 years showed virological failure and antiretroviral-resistance and thus eligible to 2nd-line treatment. Furthermore, two-third (64%) of children under 2nd-line therapy were eligible to 3rd-line regimen. Taken together, these observations point the necessity to monitor antiretroviral-treated children by plasma HIV-1 RNA load to diagnose as early as possible the therapeutic failure and operate switch to a new therapeutic line.

Human papillomavirus infection in women in four regions of Senegal.

Cervical cancer is the most frequent cancer among women in Senegal. However, there are few data concerning the human papillomavirus (HPV) types inducing neoplasia and cervical cancers and their prevalence in the general population of Senegal. The aim of this study is to determine the prevalence of HPV infection in Senegalese women aged 18 years and older in Dakar Region and three other regions. Cervical samples were collected from 498 women aged 18-80 years (mean, 42.1 years) in Dakar Region. Also, 438 samples were collected from three other regions: Thiès, Saint-Louis, and Louga. The samples were screened for 21 HPV genotypes using an HPV type-specific E7 PCR bead-based multiplex genotyping assay (TS-MPG). The prevalence of high risk (HR)-HPV in Dakar Region was 17.4%. HPV 52 (3.2%) was the most prevalent HPV type, followed by HPV 31 (3.0%) and HPV 16, 45, and 53 (all 2.8%). In the Thiès, Saint-Louis, and Louga Regions, the prevalence of HR-HPV was 23.2%, 13.1%, and 19.4%, respectively. The study revealed the specificity of HPV prevalence in Dakar Region and other regions of Senegal. The observed patterns show some differences compared with other regions of the world. These findings raise the possibility that, in addition to HPV 16 and HPV 18, other HPV types should be considered for a vaccination program in Senegal. However, additional studies to determine the HPV type distribution in cervical cancer specimens in Senegal are required to further corroborate this hypothesis.

Reduction in risk-taking behaviors among MSM in Senegal between 2004 and 2007 and prevalence of HIV and other STIs. ELIHoS Project, ANRS 12139.

An epidemiological survey conducted in Senegal in 2004 among men having sex with men (MSM) revealed high HIV prevalence and a high rate of risky behaviors within this population. Consequently, several prevention campaigns targeting MSM were implemented. A second survey was carried out in 2007 to assess the impact of these measures. This paper aims to examine trends in HIV and STI prevalence and in sexual behaviors between 2004 and 2007. The two surveys were conducted in four urban sites among 440 and 501 MSM--recruited using the snowball sampling method--in 2004 and 2007, respectively. A similar methodology was applied for both surveys. This consisted of a closed-ended questionnaire concerning socio-demographic, behavioral, and biomedical information plus a clinical examination including urine and blood tests to detect STIs and HIV infection. Between 2004 and 2007, the frequency of different sexual practices reported by MSM remained stable, but condom use for each type of sexual practice rose. The percentage of men who reported consistent condom use during previous-month anal sex has increased by about 35% (p<0.01). The percentage of men who reported consistent condom use during previous-month non-commercial sex with women has increased by 14% (p<0.01). HIV prevalence remained stable from 22.4% [95% CI: 18.6-26.8] in 2004 to 21.8% [95% CI: 18.3-25.7] in 2007 (adjusted OR = 1.05, p=0.8). Gonorrhea prevalence decreased from 5.5% [95% CI: 3.6-8.3] in 2004 to 2.6% [95% CI: 1.5-4.5] in 2007 (adjusted OR=0.5, p=0.07). The prevention campaigns, STI and HIV care and support programs conducted in Senegal among MSM have been followed by a reduction of risk-taking behaviors and STI prevalence among this population. Specific targeting of this group within HIV/STI prevention programs seems to be effective in decreasing sexual infections.

Long-term benefits of highly active antiretroviral therapy in Senegalese HIV-1-infected adults.

OBJECTIVES: To assess the long-term survival, as well as the immunologic and virologic effectiveness, adherence, and drug resistance, in HIV-infected patients receiving highly active antiretroviral therapy (HAART) in one of the oldest and best-documented African cohorts. METHODS: A prospective observational cohort study included the first 176 HIV-1-infected adults followed in the Senegalese government-sponsored antiretroviral therapy initiative launched in August 1998. Patients were followed for a median of 30 months (interquartile range, 21-36 months). HAART comprised 2 nucleoside reverse transcriptase inhibitors and either 1 protease inhibitor or 1 nonnucleoside reverse transcriptase inhibitor. RESULTS: At baseline, 92% of patients were antiretroviral naive and 82% had AIDS; the median CD4 count was 144 cells/mm, and median viral load was 202,368 copies/mL. The survival probability was high (0.81 at 3 years; 95% CI, 0.74-0.86) and was independently related to a baseline hemoglobin level <10 g/dL and a Karnofsky score <90%. Antiviral efficacy was consistently observed during the 3 years of treatment (-2.5 to -3.0 log10 copies/mL; 60-80% of patients with viral load <500 copies/mL) and the CD4 count increase reached a median of 225 cells/mm. Most patients reported good adherence (80-90%). The emergence of drug resistance was relatively rare (12.5%). CONCLUSION: This study shows that clinical and biologic results similar to those seen in Western countries can be achieved and sustained during the long term in Africa.