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Background To eliminate hepatitis B virus (HBV) infection, it is essential to scale up testing and treatment. However, conventional tools to assess treatment eligibility, particularly nucleic acid testing (NAT) to quantify HBV DNA, are hardly available and affordable in resource-limited countries. We therefore assessed the performance of a novel immunoassay, hepatitis B core-related antigen (HBcrAg), as an inexpensive (US$ Methods Using a well-characterized cohort of treatment-naive patients with chronic HBV infection in The Gambia, we evaluated the accuracy of serum HBcrAg to diagnose HBV DNA levels and to indicate treatment eligibility determined by the American Association for the Study of Liver Diseases, based on reference tests (HBV DNA, hepatitis B e antigen, alanine aminotransferase, liver histopathology, and/or FibroScan). Results A total of 284 treatment-naive patients were included in the analysis. The area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity of serum HBcrAg were 0.88 (95% confidence interval [CI], .82–.93), 83.3%, and 83.9%, respectively, to diagnose HBV DNA ≥2000 IU/mL; and 0.94 (95% CI, .88–.99), 91.4%, and 93.2% for ≥200 000 IU/mL. A simplified treatment algorithm using HBcrAg without HBV DNA showed high AUROC (0.91 [95% CI, .88–.95]) with a sensitivity of 96.6% and specificity of 85.8%. Conclusions HBcrAg might be an accurate alternative to HBV DNA quantification as a simple and inexpensive tool to identify HBV-infected patients in need of antiviral therapy in low- and middle-income countries.

Background & Aims To eliminate hepatitis B virus (HBV) infection, it is essential to scale up antiviral treatment through decentralized services. However, access to the conventional tools to assess treatment eligibility (liver biopsy/Fibroscan®/HBV DNA) is limited and not affordable in resource-limited countries. We developed and validated a simple score to easily identify patients in need of HBV treatment in Africa. Methods As a reference, we used treatment eligibility determined by the European Association for the Study of the Liver based on alanine aminotransferase (ALT), liver histology and/or Fibroscan and HBV DNA. We derived a score indicating treatment eligibility by a stepwise logistic regression using a cohort of chronic HBV infection in The Gambia (n = 804). We subsequently validated the score in an external cohort of HBV-infected Africans from Senegal, Burkina Faso, and Europe (n = 327). Results Out of several parameters, two remained in the final model, namely HBV e antigen (HBeAg) and ALT level, constituting a simple score (treatment eligibility in Africa for the hepatitis B virus: TREAT-B). The score demonstrated a high area under the receiver operating characteristic curve (0.85, 95% CI 0.79–0.91) in the validation set. The score of 2 and above (HBeAg-positive and ALT ≥20 U/L or HBeAg-negative and ALT ≥40 U/L) had a sensitivity and specificity for treatment eligibility of 85% and 77%, respectively. The sensitivity and specificity of the World Health Organization criteria based on the aspartate aminotransferase-to-platelet ratio index (APRI) and ALT were 90% and 40%, respectively. Conclusions A simple score based on HBeAg and ALT had a high diagnostic accuracy for the selection of patients for HBV treatment. This score could be useful in African settings. Lay summary Limited access to the diagnostic tools used to assess treatment eligibility (liver biopsy/Fibroscan/hepatitis B virus DNA) has been an obstacle to the scale up of hepatitis B treatment programs in low- and middle-income countries. Using the data from African patients with chronic HBV infection, we developed and validated a new simple diagnostic score for treatment eligibility, which only consists of hepatitis B virus e antigen and alanine aminotransferase level. The diagnostic accuracy of the score for selecting patients for HBV treatment was high and could be useful in African settings.

Objective Maternal-to-child-transmission of HIV-1 infection remains a significant cause of HIV-1 infection despite successful prevention strategies. Testing protective HIV-1 vaccines remains a critical priority. The immunogenicity of ALVAC-HIV vCP1521 (ALVAC) in infants born to HIV-1-infected women in Uganda was evaluated in the first pediatric HIV-1 vaccine study in Africa. Design HIV Prevention Trials Network 027 was a randomized, double-blind, placebo-controlled phase I trial to evaluate the safety and immunogenicity of ALVAC in 60 infants born to HIV-1-infected mothers with CD4 counts of >500 cells per microliter, which were randomized to the ALVAC vaccine or placebo. ALVAC-HIV vCP1521 is an attenuated recombinant canarypox virus expressing HIV-1 clade E env, clade B gag, and protease gene products. Methods Infants were vaccinated at birth and 4, 8, and 12 weeks of age with ALVAC or placebo. Cellular and humoral immune responses were evaluated using interferon-γ enzyme-linked immunosorbent spot, carboxyfluorescein diacetate succinimidyl ester proliferation, intracellular cytokine staining, and binding and neutralizing antibody assays. Fisher exact test was used to compare positive responses between the study arms. Results Low levels of antigen-specific CD4 and CD8 T-cell responses (intracellular cytokine assay) were detected at 24 months (CD4-6/36 vaccine vs. 1/9 placebo; CD8-5/36 vaccine vs. 0/9 placebo) of age. There was a nonsignificant trend toward higher cellular immune response rates in vaccine recipients compared with placebo. There were minimal binding antibody responses and no neutralizing antibodies detected. Conclusions HIV-1-exposed infants are capable of generating low levels of cellular immune responses to ALVAC vaccine, similar to responses seen in adults.

Comment in : Screen-and-treat for chronic hepatitis B: an overdue issue for sub-Saharan Africa./Allain JP. Lancet Glob Health. 2016 Aug;4(8):e507-8. doi: 10.1016/S2214-109X(16)30140-1. PMID: 27443770; International audience; Background: Despite the introduction of immunisation for hepatitis B virus (HBV) in the 1990s, HBV-related morbidity and mortality remain high in sub-Saharan Africa. Identification and treatment of asymptomatic people with chronic HBV infection should reduce the disease burden. We therefore assessed the feasibility of a screen-and-treat programme for HBV infection in The Gambia, west Africa, and estimated the proportion of HBV-infected people who had significant liver disease in need of treatment.Methods: Between Dec 7, 2011, and Jan 24, 2014, individuals living in randomly selected communities in western Gambia were offered hepatitis B surface antigen (HBsAg) screening via a point-of-care test. The test was also offered to potential blood donors attending the central hospital in the capital, Banjul. HBsAg-positive individuals were invited for a comprehensive liver assessment and were offered treatment according to international guidelines. We defined linkage to care as visiting the liver clinic at least once. Eligibility for treatment was judged in accordance with the 2012 European Association for the Study of the Liver guidelines.Findings: HBsAg screening was accepted by 5980 (weighted estimate 68·9%, 95% CI 65·0-72·4) of 8170 adults from 27 rural and 27 urban communities and 5559 (81·4%, 80·4-82·3) of 6832 blood donors. HBsAg was detected in 495 (8·8%, 7·9-9·7) individuals in communities and 721 (13·0%, 12·1-13·9) blood donors. Prevalence was higher in men (239 [10·5%, 8·9-12·1] of 2328 men vs 256 [7·6%, 6·5-8·7] of 3652 women; p=0·004) and middle-aged participants. Linkage to care was high in the communities, with 402 (81·3%) of 495 HBsAg-positive individuals attending the clinic. However, only 300 (41·6%) of 721 HBsAg-positive people screened at the blood bank linked into care. Of those who attended the clinic, 18 (4·4%, 2·5-7·7) patients from the communities and 29 (9·7%, 6·8-13·6) from the blood bank were eligible for treatment. Male sex was strongly associated with treatment eligibility (odds ratio 4·35, 1·50-12·58; p=0·007).Interpretation: HBV infection remains highly prevalent in The Gambia. The high coverage of community-based screening, good linkage into care, and the small proportion of HBsAg carriers who need treatment suggest that large-scale screening and treatment programmes are feasible in sub-Saharan Africa.Funding: European Commission (FP7).

International audience; Background: Simple and inexpensive non-invasive fibrosis tests are highly needed but have been poorly studied in sub-Saharan Africa.Methods: Using liver histology as a gold standard, we developed a novel index using routine laboratory tests to predict significant fibrosis in patients with chronic HBV infection in The Gambia, West Africa. We prospectively assessed the diagnostic accuracy of the novel index, Fibroscan, aspartate transaminase-to-platelet ratio index (APRI), and Fib-4 in Gambian patients with CHB (training set) and also in French and Senegalese CHB cohorts (validation sets).Results: Of 135 consecutive treatment-naïve patients with CHB who had liver biopsy, 39% had significant fibrosis (Metavir fibrosis stage ≥F2) and 15% had cirrhosis (F4). In multivariable analysis, gamma-glutamyl transpeptidase (GGT) and platelet count were independent predictors of significant fibrosis. Consequently, GGT-to-platelet ratio (GPR) was developed. In The Gambia, the area under the receiver operating characteristic curve (AUROC) of the GPR was significantly higher than that of APRI and Fib-4 to predict ≥F2, ≥F3 and F4. In Senegal, the AUROC of GPR was significantly better than Fib-4 and APRI for ≥F2 (0.73, 95% CI 0.59 to 0.86) and better than Fib-4 and Fibroscan for ≥F3 (0.93, 0.87 to 0.99). In France, the AUROC of GPR to diagnose ≥F2 (0.72, 95% CI 0.59 to 0.85) and F4 (0.87, 0.76 to 0.98) was equivalent to that of APRI and Fib-4.Conclusions: The GPR is a more accurate routine laboratory marker than APRI and Fib-4 to stage liver fibrosis in patients with CHB in West Africa. The GPR represents a simple and inexpensive alternative to liver biopsy and Fibroscan in sub-Saharan Africa.

Summary Background In sub-Saharan Africa, it is unknown whether hepatitis E virus (HEV) infection is a common precipitating event of acute-on-chronic liver failure (ACLF). Aims To estimate the prevalence of HEV infection in general population and assess whether HEV is a common trigger of ACLF in cirrhotic patients in The Gambia, West Africa. Methods We first conducted an HEV sero-survey in healthy volunteers. We then tested cirrhotic patients with ACLF (cases) and compensated cirrhosis (controls) for anti-HEV IgG as a marker of exposure to HEV, and anti-HEV IgA and HEV RNA as a marker of recent infection. We also described the characteristics and survival of the ACLF cases and controls. Results In the healthy volunteers (n = 204), 13.7% (95% CI: 9.6–19.2) were positive for anti-HEV IgG, and none had positive HEV viraemia. After adjusting for age and sex, the following were associated with positive anti-HEV IgG: being a Christian, a farmer, drinking water from wells, handling pigs and eating pork. In 40 cases (median age: 45 years, 72.5% male) and 71 controls (39 years, 74.6% male), ≥70% were infected with hepatitis B virus. Although hepatitis B flare and sepsis were important precipitating events of ACLF, none had marker of acute HEV. ACLF cases had high (70.0%) 28-day mortality. Conclusions Hepatitis E virus infection is endemic in The Gambia, where both faecal-oral route (contaminated water) and zoonotic transmission (pigs/pork meat) may be important. However, acute HEV was not a common cause of acute-on-chronic liver failure in The Gambia.

International audience; Background & aims: Early age at infection with Hepatitis B virus (HBV) increases the risk of chronic infection. Moreover, early HBV infection may further independently increase the risk of hepatocellular carcinoma (HCC) beyond its effect on chronicity.Methods: The distribution of birth order, a proxy for mode and timing of HBV transmission, was compared in The Gambia between hepatitis B surface antigen (HBsAg)-positive HCC cases recruited from hospitals (n = 72) and two HBsAg-positive control groups without HCC: population-based controls from a community HBV screening (n = 392) and hospital-based controls (n = 63).Results: HCC risk decreased with increasing birth order in the population-based case-control analysis. Using first birth order as the reference, the odds ratios were 0.52 (95% CI: 0.20-1.36), 0.52 (0.17-1.56), 0.57 (0.16-2.05) and 0.14 (0.03-0.64) for second, third, fourth and greater than fourth birth order respectively (P = 0.01). A similar inverse association was observed in the hospital-based case-control comparison (P = 0.04).Conclusions: Compared to controls, HCC cases had earlier birth order, a proxy for young maternal age and maternal HBV viraemia at birth. This finding suggests that in chronic HBV carriers perinatal mother-to-infant transmission may increase HCC risk more than horizontal transmission. Providing HBV vaccine within 24 h of birth to interrupt perinatal transmission might reduce the incidence of HCC in The Gambia.

Despite infrastructure and capacity challenges in Africa, significant development has been made in the number of laboratories supporting immunological and safety studies required for large-scale HIV/AIDS vaccine or intervention trials. In Uganda, cohorts participating in HIV intervention trials are often recruited from rural areas. To avoid transporting samples from intervention trial areas over long distances (120 km) to central laboratories in Entebbe, we set up a standardized peripheral blood mononuclear cells (PBMCs) processing laboratory at a field station in Masaka, southwest Uganda. The laboratory was well equipped and enrolled into the International AIDS Vaccine Initiative (IAVI) Quality Assurance (QA) program. Staff was trained in laboratory techniques and Good Clinical Laboratory Practice (GCLP). The laboratory received IAVI and GCLP accreditation in 2008. In this paper we describe the process and achievements of measures taken to overcome challenges, to build staff capacity, and to optimize the quality of the cells yielded. * PBMCs : peripheral blood mononuclear cells IAVI : International AIDS Vaccine Initiative QA : quality assurance GCLP : Good Clinical Laboratory Practice CTL : cytotoxic T lymphocytes Th : T helper UVRI : Uganda Virus Research Institute SOPs : standard operating procedures SPARTAC : short pulse anti-retroviral treatment at seroconversion S101 : sample 1, operator 1 S1O2 : sample 1, operator 2 S2O1 : sample 2, operator 1 S2O2 : sample 2, operator 2 ELISPOT : enzyme-linked immunosorbent spot CLS : Clinical Support laboratory DAIDS : division of AIDS

International audience; Background: The natural history of chronic HBV infection in sub-Saharan Africa is unknown. Data are required to inform WHO guidelines that are currently based on studies in Europe and Asia.Methods: Between 1974 and 2008, serosurveys were repeated in two Gambian villages, and an open cohort of treatment-naive chronic HBV carriers was recruited. Participants were followed to estimate the rates of hepatitis B e (HBeAg) and surface antigen (HBsAg) clearance and incidence of hepatocellular carcinoma (HCC). In 2012-2013, a comprehensive liver assessment was conducted to estimate the prevalence of severe liver disease.Results: 405 chronic carriers (95% genotype E), recruited at a median age of 10.8 years, were followed for a median length of 28.4 years. Annually, 7.4% (95% CI 6.3% to 8.8%) cleared HBeAg and 1.0% (0.8% to 1.2%) cleared HBsAg. The incidence of HCC was 55.5/100 000 carrier-years (95% CI 24.9 to 123.5). In the 2012-2013 survey (n=301), 5.5% (95% CI 3.4% to 9.0%) had significant liver fibrosis. HBV genotype A (versus E), chronic aflatoxin B1 exposure and an HBsAg-positive mother, a proxy for mother-to-infant transmission, were risk factors for liver fibrosis. A small proportion (16.0%) of chronic carriers were infected via mother-to-infant transmission; however, this population represented a large proportion (63.0%) of the cases requiring antiviral therapy.Conclusions: The incidence of HCC among chronic HBV carriers in West Africa was higher than that in Europe but lower than rates in East Asia. High risk of severe liver disease among the few who are infected by their mothers underlines the importance of interrupting perinatal transmission in sub-Saharan Africa.

Hepatitis B virus (HBV) infection is a leading cause of death in sub-Saharan Africa (SSA). Point-of-care tests for hepatitis B surface antigen (HBsAg) could be an ideal tool for a large-scale HBV screening/treatment program in SSA. Using data from the PROLIFICA (Prevention of Liver Fibrosis and Cancer in Africa) program, we conducted a cross-sectional study to assess the diagnostic accuracy of three point-of-care tests (Determine, Vikia, and Espline) for the detection of HBsAg in the field or a laboratory setting in the Gambia. In the field, we used finger-prick whole blood for the Determine and Vikia tests and dried blood spots for the reference standard test (AxSYM HBsAg enzyme-linked immunosorbent assay [ELISA]). In the laboratory we used serum for the Determine, Espline, and reference test (Architect chemiluminescent microparticle immunoassay). Of 773 participants recruited at the community and 227 known chronic HBV carriers (1,000 subjects in total), 293 were positive for HBsAg. The sensitivity and specificity of the Determine test were 88.5% and 100% in the field and 95.3% and 93.3% in the laboratory setting, respectively. The sensitivity and specificity were 90.0% and 99.8% for the Vikia test (in the field) and 93.9% and 94.7% for the Espline test (in the laboratory). There was no evidence that one kit was better than another. Most of the patients with false-negative results (18/19) were classified as inactive chronic carriers. In summary, the three point-of-care tests had acceptable ranges of diagnostic accuracy. These tests may represent accurate, rapid, and inexpensive alternatives to serology testing for the screening of HBV infection at field level in SSA.

International audience

There is no clinically applicable biomarker for surveillance of hepatocellular carcinoma (HCC), because the sensitivity of serum alpha-fetoprotein (AFP) is too low for this purpose. Here, we determined the diagnostic performance of a panel of urinary metabolites of HCC patients from West Africa. Urine samples were collected from Nigerian and Gambian patients recruited on the case-control platform of the Prevention of Liver Fibrosis and Cancer in Africa (PROLIFICA) program. Urinary proton nuclear magnetic resonance (1H-NMR) spectroscopy was used to metabolically phenotype 290 subjects: 63 with HCC; 32 with cirrhosis (Cir); 107 with noncirrhotic liver disease (DC); and 88 normal control (NC) healthy volunteers. Urine samples from a further cohort of 463 subjects (141 HCC, 56 Cir, 178 DC, and 88 NC) were analyzed, the results of which validated the initial cohort. The urinary metabotype of patients with HCC was distinct from those with Cir, DC, and NC with areas under the receiver operating characteristic (AUROC) curves of 0.86 (0.78-0.94), 0.93 (0.89-0.97), and 0.89 (0.80-0.98) in the training set and 0.81 (0.73-0.89), 0.96 (0.94-0.99), and 0.90 (0.85-0.96), respectively, in the validation cohort. A urinary metabolite panel, comprising inosine, indole-3-acetate, galactose, and an N-acetylated amino acid (NAA), showed a high sensitivity (86.9% [75.8-94.2]) and specificity (90.3% [74.2-98.0]) in the discrimination of HCC from cirrhosis, a finding that was corroborated in a validation cohort (AUROC: urinary panel = 0.72; AFP = 0.58). Metabolites that were significantly increased in urine of HCC patients, and which correlated with clinical stage of HCC, were NAA, dimethylglycine, 1-methylnicotinamide, methionine, acetylcarnitine, 2-oxoglutarate, choline, and creatine. Conclusion: The urinary metabotyping of this West African cohort identified and validated a metabolite panel that diagnostically outperforms serum AFP. (Hepatology 2014;60:1291–1301)

The mechanisms underlying the relatively slow progression of human immunodeficiency virus type 2 (HIV-2) compared with HIV-1 infection are undefined and could be a result of more effective immune responses. We used HIV-2 and HIV-1 IFN-γ enzyme-linked immunospot assays to evaluate CD8+ T cell responses in antiretroviral-naive HIV-2-('HIV-2+') and HIV-1-infected ('HIV-1+') individuals. Gag-specific responses were detected in the majority of HIV-2+ and HIV-1+ subjects. Overlapping gag peptide analysis indicated a significantly greater magnitude and breadth of responses in the HIV-1+ cohort, and this difference was attributable to low responses in HIV-2+ subjects with undetectable viral load (medians 2107 and 512 spot-forming units per 106 PBMC, respectively, p=0.007). We investigated the phenotype of viral epitope-specific CD8+ T cells identified with HLA-B53- and HLA-B58-peptide tetramers (8 HIV-2+, 11 HIV-1+ subjects). HIV-2-specific CD8+ T cells were predominantly CD27+ CD45RA-, and only a minority expressed perforin. The limited breadth and low frequency of CD8+ T cell responses to HIV-2 gag in aviremic HIV-2+ subjects suggests that these responses reflect antigen load in plasma, as is the case in HIV-1 infection. Immune control of HIV-2 does not appear to be related to the frequency of perforin-expressing virus-specific CD8+ T cells. © 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.

International audience; In The Gambia, West Africa, the prevalence of chronic hepatitis B virus (HBV) infection in adults exceeds eight percent and hepatocellular carcinoma (HCC) has been the most frequent type of malignancy. Two population-based intervention studies to control HBV infection, namely, GHIS (Gambia Hepatitis Intervention Study) and PROLIFICA (Prevention of Liver Fibrosis and Cancer in Africa), are discussed. The GHIS started in 1986 as a nation-wide trial of the HBV vaccine to evaluate the effectiveness of infant HBV vaccination in preventing HCC in adulthood. The vaccine was progressively introduced into the Expanded Program of Immunization (EPI) of The Gambia over four years in a phased manner, called the "stepped-wedge" design. This was because instantaneous universal vaccination in the country was impossible for logistic and financial reasons. However, this design also allowed the study to have an unvaccinated control group which consisted of the newborns of the areas where HBV vaccine has not yet been incorporated in the EPI. To assess the outcome, a national cancer registry was founded and all HCC patients in this birth cohort are linked with the vaccine trial database. The study is still ongoing to answer whether the HBV vaccine in infancy prevent HCC in adulthood in The Gambia. Although the universal HBV vaccination since 1990 has been successful in reducing the prevalence of chronic HBV infection in young Gambians, the number of HCC cases may not decline over the next decades as people infected prior to the immunization program are likely to continue to develop the diseases. To reduce the HCC incidence through community-based screening of HBV infection and provision of antiviral therapy, the PROLIFICA project started in 2011. Study hypothesis and design of these two studies, GHIS and PROLIFICA, are further discussed.

Summary Background By increasing the hepatic blood circulation, food intake has been suggested to increase liver stiffness measurement (LSM) values in HCV-infected patients. Aim To investigate prospectively the effects of food intake on LSM in hepatitis B virus (HBV)-infected patients and healthy controls. Methods In The Gambia, patients included in the PROLIFICA project are screened for HBV at the community level and then invited for fasting assessment including LSM. Between April 2012 and October 2012, each day, the first five participants were invited to participate in this study. After the initial examination, a standardised 850 Kcal breakfast was provided. Effect of food intake was assessed by examining mean difference of LSM, IQR and IQR/LSM at T0 (fasting LSM1), T30min (LSM2) and T120min (LSM3) respectively. Results A total of 209 subjects were enrolled in this study (133 were HBV positive, 76 healthy controls). Unreliable measurements occurred more frequently after food intake (5%, 24% and 18% at T0, T30min and T120min respectively). In both groups, median LSM2 was significantly higher than LSM1 [6.2 (IQR: 5.4, 7.9)] vs. 4.9 (4.2, 6.2), P

BACKGROUND: Increased understanding of the genetic diversity of HIV-1 is challenging but important in the development of an effective vaccine. We aimed to describe the distribution of HIV-1 subtypes in northern Tanzania among women enrolled in studies preparing for HIV-1 prevention trials (hospitality facility-worker cohorts), and among men and women in an open cohort demographic surveillance system (Kisesa cohort). METHODS: The polymerase encompassing partial reverse transcriptase was sequenced and phylogenetic analysis performed and subtype determined. Questionnaires documented demographic data. We examined factors associated with subtype using multinomial logistic regression, adjusted for study, age, and sex. RESULTS: Among 140 individuals (125 women and 15 men), subtype A1 predominated (54, 39%), followed by C (46, 33%), D (25, 18%) and unique recombinant forms (URFs) (15, 11%). There was weak evidence to suggest different subtype frequencies by study (for example, 18% URFs in the Kisesa cohort versus 5-9% in the hospitality facility-worker cohorts; adjusted relative-risk ratio (aRR) = 2.35 [95% CI 0.59,9.32]; global p = 0.09). Compared to men, women were less likely to have subtype D versus A (aRR = 0.12 [95% CI 0.02,0.76]; global p = 0.05). There was a trend to suggest lower relative risk of subtype D compared to A with older age (aRR = 0.44 [95% CI 0.23,0.85] per 10 years; global p = 0.05). CONCLUSIONS: We observed multiple subtypes, confirming the complex genetic diversity of HIV-1 strains circulating in northern Tanzania, and found some differences between cohorts and by age and sex. This has important implications for vaccine design and development, providing opportunity to determine vaccine efficacy in diverse HIV-1 strains.

Background CRF02_AG is the predominant HIV strain circulating in West and West Central Africa. The aim of this study was to test whether this predominance is associated with a higher in vitro replicative fitness relative to parental subtype A and G viruses. Primary HIV-1 isolates (10 CRF02_AG, 5 subtype A and 5 subtype G) were obtained from a well-described Cameroonian cohort. Growth competition experiments were carried out at equal multiplicity of infection in activated T cells and monocyte-derived dendritic cells (MO-DC) in parallel. Results Dual infection/competition experiments in activated T cells clearly indicated that CRF02_AG isolates had a significant replication advantage over the subtype A and subtype G viruses. The higher fitness of CRF02_AG was evident for isolates from patients with CD4+ T cell counts >200 cells/μL (non-AIDS) or CD4+ T cell counts Conclusion We observed a higher ex vivo replicative fitness of CRF02_AG isolates compared to subtype A and G viruses from the same geographic region and showed that this was independent of the co-receptor tropism and irrespective of high or low CD4+ T cell count. This advantage in replicative fitness may contribute to the dominant spread of CRF02_AG over A and G subtypes in West and West Central Africa.

We have developed and validated an oligonucleotide probe hybridization assay for human immunodeficiency virus type 1 (HIV-1) circulating recombinant form (CRF) CRF02_AG. In the p17 coding region of the gag gene, a CRF02_AG-specific signature pattern was observed. Five working probes were designed to discriminate CRF02_AG infections from infections by all other documented subtypes and CRFs in an enzyme-linked immunosorbent assay-based oligonucleotide probe hybridization assay. Nucleic acids were extracted from a panel of HIV-1-positive plasma samples from Cameroon, Bénin, Côte d'Ivoire, Kenya, Zambia, and Belgium and from blood spots from The Gambia. CRF02_AG ( n = 147) and non-CRF02 ( n = 100) samples were analyzed to evaluate and validate the oligonucleotide probe hybridization assay. The CRF02_AG-specific oligonucleotide probe hybridization assay has a high sensitivity and specificity, with good positive and negative predictive values in regions of high and low prevalence. A validation of the assay with West and West Central African samples indicated a sensitivity of 98.4% and a specificity of 96.7%. The oligonucleotide probe hybridization assay as a diagnostic tool will allow for rapid screening for CRF02_AG. This could be used to track the HIV epidemic in terms of documenting the real prevalence of CRF02_AG strains and will complement efforts in vaccine development. Moreover, this technology can easily be applied in laboratories in developing countries.

Background: During the last decades, outbreaks of hand-footmouthdisease (HFMD)havebeen reported formany times inChina. The prevention and control of it has become an issue. Presently, there are no specific treatments and specific antiviral drugs or vaccines available against non-polio enteroviruses causingHFMD. That means the risk of infection only can be reduced by good hygiene practices and early medical attention for children with severe symptoms. Therefore, early detection and response using mathematical statistics method during the epidemics will be helpful for policy-makers to generate preventive strategies. Methods & Materials: We proposed a multiple seasonal autoregressive integrated moving average model, to forecast the expected incidence from April 2013 to September 2013 using the retrospective incidence from January 2008 to December 2012 as training set, and incidence from January 2013 to March 2013 as validation set obtained from China Information System for Disease Control and Prevention (CISDCP). All the procedures were implemented via SAS9.2 system. Results: After one order of regular differencing and one order of seasonal differencing, the transformed series achieved stationary. The best fitted model was SARIMAwith the lowest value of Bayesian Information Criterions (BIC). Model parameters had significant differences (P 0.05) (Table 2). This indicated that the best fitted model extracted the useful information of the series. Predictions and observations were very close to each other and showed a good forecasting performance. Conclusion: The ARIMA model we proposed can be an effective way to forecast the incidence cases of HFMD. Detecting the outbreaks before they happened is the key point of the early detection and early warning, and that is also the main purpose of our study. The usefulness of forecasting expected incidence of HFMD performs not only in giving public-health officials a probable trend of the variability to be expected in the future, but also in detecting outbreaks and providing probability statements and guidance to policy makers.

Human immunodeficiency virus type-1 (HIV-1) cytotoxic T lymphocyte (CTL) epitopes have largely been defined in Caucasian populations infected with clade B virus. Identification of potentially protective CTL epitopes in non-B clade-infected African subjects is important for vaccine development. In a study of CTL responses in clade A-infected Gambians, using cytotoxicity, interferon-gamma (IFN-gamma) enzyme-linked immunospot (ELISpot) and HLA-B53-peptide tetramer assays, we identified three HLA-B53-restricted epitopes in HIV-1 gag p24. CTL specific for an epitope in a highly immunogenic region of the p24 protein showed no cross-reactivity to other HIV-1 clades. Two of the epitopes would not have been predicted from the peptide-binding motif due to the absence of a proline anchor at position 2. Structural analysis of HLA-B53 and its relative, HLA B35, enabled us to re-define the peptide-binding motif to include other P2 anchors. These results demonstrate the value of combined immunological and structural analyses in defining novel CTL epitopes and have implications for HIV-1 vaccine design.

nant genome from the American continent, which exhibited a HBV/A2 DNA region (nucleotide positions 147–636 of the S gene) inserted in a backbone corresponding to HBV/D3. Hence, the aim of this study was to preliminary analyse the very early replication dynamics of the infection of this HBV D/A recombinant in comparison to its parental genotypes (HBV/D and HBV/A) and to a highly replicative genotype (HBV/C) in an in vitro experimental system. pUC19 plasmids deprived of promoters and carrying 1.24fold the HBV genome of HBV/A2, D3, C and D/A recombinant were constructed. Huh7 cells were transfected with these plasmids and transfection efficiency was monitored by using a pTARGET -GFP expression vector. At 24 and 72 h post-transfection (hpt), ALT/AST levels, viral load (COBAS TaqMan HBV Test, Roche), HBsAg and HBeAg (Abbott) were determined in supernatants. Cells were lysed at 72 hpt and the density of core associated-HBV DNA was compared by Southern blot hybridization. Except for Southern Blot, all experiments were conducted twice for each clone. Student’s t-test was used to compare the means and standard deviations between any pair of samples. A p value 0.05). Negative controls processed in parallel confirmed the specificity of the above mentioned results. Since this recombinant was obtained from an injecting drug user, these results imply an unprecedented call of singular relevance for the regional public health. Further in vivo studies are urgently needed to determine the pathogenicity of these replicative competent clones.

47 TESTING FOR HEPATITIS B VIRUS (HBV) ALONE DOES NOT INCREASE VACCINE COVERAGE IN NON-IMMUNIZED PERSONS J. Bottero, A. Boyd, J. Gozlan, M. Lemoine, A. Collignon, N. Boo, P. Dhotte, B. Varsat, C. Charlois, O. Cha, O. Picard, M.-D. Pauti, P. Campa, B. Silbermann, M. Bary, H. Rougier, P.-M. Girard, K. Lacombe. INSERM U 707, Universite Pierre et Marie Curie, Infectious Diseases, Virology Department, Hepatology Department, Hopital Saint Antoine, Laboratoire St Marcel, Direction de l’Action Sociale, de l’Enfance et de la Sante, CDAG du Figuier, Mairie de Paris, CPAM-CNAMTS, CDAG de Belleville, Mairie de Paris, Policlinique Baudelaire, Hopital Saint Antoine, Centre d’Accueil, de Soins et d’Orientation, Medecin du Monde, Unite de Consultation et de Soins Ambulatoires, Maison d’Arret de la Sante, Centre Croix Rouge du Moulin Joly, Paris, France E-mail: julie.bottero@sat.aphp.fr

Background Sub-Saharan Africa (SSA) remains the region most affected by HIV. A safe, effective and accessible vaccine is required to complement the existing HIV/AIDS prevention strategies. Until recently, HIV vaccine research was conducted mainly in the developed world, but increasingly is taking place in developing countries. In recent years capacity for such research has been developed in SSA through the support of international partners. With the growing mandate to conduct HIV prevention research in Africa, there is need to sustain and complement this capacity building by supporting South-South networks to strengthen the existing experience and expertise.

Background Characterizing neutralizing antibody (Nab) responses in non-B HIV-1 subtypes is essential, because the data may illustrate key genetic and antibody properties that could impact the design and testing of Nab vaccine candidates in countries where these subtypes circulate. The principle objective of this study is to document the magnitude, breadth and prevalence of neutralizing antibodies in a cohort of non-B HIV chronically infected individuals in rural Uganda.