CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

with HIV (Table 1). Provincial HBV prevalence was highest in Luapula (5.1%) with the highest rates of HIV infection amongst those HBV+ in Lusaka and Western (Table 1). HBV positivity was most common amongst men, those 25-34 years of age and lowest amongst the 0-14 age group (Table 1). HBV positivity was higher among HIV positive persons (aORHIV+ vs.HIV-]=1.49, 95% CI=1.24-1.79); male sex (aORMale vs.Female=1.69, 95% CI=1.47-1.93); highest among persons residing in Luapula (aORLuapula vs.Eastern=2.19, 95% CI=1.51-3.17) and among persons aged 25-34 years (aOR25-34y vs.15-24y=1.39, 95% CI=1.16-1.66). Persons aged 35-44 years were most likely to be coinfected with HIV (aOR34- 44yvs.15-24y4= 6.61, 95% CI=3.75-11.64) as well as those residing in Western province (aORWestern vs.Eastern= 2.32, 95% CI=1.08-4.96). Conclusion: These findings highlight, for the first time in Zambia, high levels of chronic HBV infection, and a need for hepatitis B vaccination programs, screening and treatment programs, and for careful attention to national HIV and HIV/HBV treatment and pre-exposure prophylaxis guidelines.

determined using the viral epidemiology signature pattern analysis (VESPA) and DataMonkey, respectively. Results: HBV genomes from 50 (45.9%) individuals were successfully genotyped; 25 were CHB and 25 were OBI. 27 were whole genomes (18 CHB and 9 OBI), while 23 were near complete (~3kb) (7 CHB and 16 OBI). Among OBI participants, genotype A1 was identified in 12 (48%), D3 in 12 (48%), and E in 1 (4 %). Equivalent genotype proportions were observed in CHB participants. There were 43 OBI associated mutations of which 39 were novel mutations. In total, there were 83 codons under negative immune selection pressure and 2 under positive selection. Of the negatively selected codons in the CHB participants, 4 were in positions with OBI associated mutations. There were significantly more negatively selected codons in the CHB than in the OBI (p value = 0.031) sequences. There were 16 signature aa that distinguished occult from chronic HBV sequences. No drug resistance mutations were detected in this study. Conclusion: Whole genome sequences representing occult and chronic HBV were compared for the first time in Botswana. Multiple occult-associated mutations, including several novel OBI associated mutations, were identified. There were more negatively selected codons in the CHB sequences. Future studies on large sample sizes and the functional analysis of the OBI associated mutations are warranted to understand the virologic and host genetic factors that influence HBV replication and the development of occult HBV infection. 616 IN SILICO ANALYSIS OF OCCULT HBV ASSOCIATED MUTATIONS IN BOTSWANA Motswedi Anderson 1 , Wonderful T. Choga 1 , Sikhulile Moyo 1 , Tshepiso Mbangiwa 1 , Bonolo B. Phinius 1 , Theresa K. Sebunya 1 , Joseph Makhema 1 , Richard G. Marlink 2 , Max Essex 2 , Rosemary Musonda 1 , Jason T. Blackard 1 , Simani Gaseitsiwe 3 1 Botswana Harvard AIDS Inst Partnership, Gaborone, Botswana, 2 Harvard University, Cambridge, MA, USA, 3 Botswana Harvard AIDS Institute Partnership, Gabarone, Botswana Background: Occult hepatitis B infections (OBI; HBsAg negative but HBV DNA positive) represent a significant reservoir of undiagnosed and untreated HBV infection; there is a need to identify viral mutations that lead to this. Several studies of OBI have identified many occult-associated mutations than can be characterized functionally due to time-consuming and expensive nature of such studies. Fast, reliable, and cheap in silico approaches, which can predict the effect of amino acids (aa) variants on HBV protein function have been developed. This predicts the best candidates for functional analysis by distinguishing variants with a likely deleterious effect on protein function from those that likely do not have any impact. We sought to determine the functional impact of OBI-associated mutations identified in Botswana using several in silico approaches. Methods: Three computational tools; PolyPhen2, SNAP2 and PROVEAN were utilized to predict the effects of OBI mutations in protein function. Reliability of these tools was determined by testing their ability to correctly classify 68 previously characterised occult-associated mutations as deleterious from previous studies. Studies that included HBV genotype information for the viral background including in the functional analysis were included for confirmation of tool reliability. The mutation was considered deleterious to protein function if detected by at least 2 tools. Using the same algorithm, we determined the impact of 43 OBI associated mutations we recently identified by comparing whole genome sequences of chronic HBV infected against those of OBI individuals in Botswana. Results: PolyPhen2 and PAN2 predicted 52 (76.5%) and 55 (80.9%) of previously characterised mutations as deleterious, respectively. PROVEAN detected 65 (95.6%). A total of 59 (86.8%) of the previously characterized mutations were correctly predicted as deleterious by at least two tools (Figure1). In this study, 26 of the 43 OBI associated mutations from Botswana identified were predicted to have an impact on protein function, most of which were in the surface and core regions. Conclusion: The majority of occult-associated mutations from Botswana were predicted as having an impact on protein function. To our knowledge, this is the first study to use an in silico approach to determine the impact of OBI associated mutations, thereby identifying potential candidates for functional analysis studies.

Poster Abstracts

615 NEAR FULL LENGTH GENOMES OF CHRONIC AND OCCULT HBV FROM HIV PATIENTS IN BOTSWANA Motswedi Anderson 1 , Wonderful T. Choga 1 , Sikhulile Moyo 1 , Bonolo B. Phinius 1 , Tshepiso Mbangiwa 1 , Lynnette Bhebhe 2 , Theresa K. Sebunya 3 , Richard G. Marlink 4 , Max Essex 4 , Rosemary Musonda 1 , Jason T. Blackard 5 , Simani Gaseitsiwe 6 1 Botswana Harvard AIDS Inst Partnership, Gaborone, Botswana, 2 National University of Science and Technology, Bulawayo, Zimbabwe, 3 University of Botswana, Gaborone, Botswana, 4 Harvard University, Cambridge, MA, USA, 5 University of Cincinnati, Cincinnati, OH, USA, 6 Botswana Harvard AIDS Institute Partnership, Gabarone, Botswana Background: The World Health Organization plans to eradicate viral hepatitis by 2030; therefore, there is a need to study and understand the HBV virus further. It is important to evaluate occult HBV infections (OBI; HBsAg negative but HBV DNA positive) given that it is frequently undiagnosed and rarely treated. Few full-length OBI genomes are available, due to its low viremia. We aimed to molecularly characterize nearly full length HBV genomes from HIV co-infected individuals with chronic or occult HBV in Botswana. Methods: This was a cross-sectional study of 109 individuals from previous HIV studies conducted at Botswana Harvard Partnership from 2009 to 2012. Full-length (3.2kb) and nearly full-length genomes (~3kb) were amplified by nested PCR. Sequences from OBI participants were compared to GenBank references and participants with chronic HBV (CHB) to identify occult-associated mutations. Signature amino acids (aa) and immune selection pressures were

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