{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:40:52Z","timestamp":1760190052151,"version":"build-2065373602"},"reference-count":22,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2019,6,19]],"date-time":"2019-06-19T00:00:00Z","timestamp":1560902400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000200","name":"United States Agency for International Development","doi-asserted-by":"publisher","award":["GPO-A-00-05-00022-00"],"award-info":[{"award-number":["GPO-A-00-05-00022-00"]}],"id":[{"id":"10.13039\/100000200","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["5R24TW008863"],"award-info":[{"award-number":["5R24TW008863"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000061","name":"Fogarty International Center","doi-asserted-by":"publisher","award":["D43TW00231"],"award-info":[{"award-number":["D43TW00231"]}],"id":[{"id":"10.13039\/100000061","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Intermittent use of a single antiretroviral agent in the presence of a replicating virus could potentially increase the development of antiviral resistance. The pericoital, before-and-after sex, dosing regimen used in the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 tenofovir gel trial meant that women who were infected with hepatitis B virus (HBV) were exposed intermittently to tenofovir during their participation. The impact of this dosing regimen on HBV resistance was assessed by amplification of the HBV polymerase region from 37 stored plasma samples of women who were HBV surface antigen positive. All samples belonged to HBV genotype A. None of the known tenofovir resistance mutations (M240V\/I, L180M, A194T, V214A, N238T) were identified in any individuals. While it is reassuring that no resistance mutations were found among women using topical tenofovir, the rapidly expanding access to oral tenofovir-containing HIV pre-exposure prophylaxis (PrEP), with higher systemic exposure to the drug, makes monitoring for potential HBV drug resistance important.<\/jats:p>","DOI":"10.3390\/v11060569","type":"journal-article","created":{"date-parts":[[2019,6,19]],"date-time":"2019-06-19T10:43:32Z","timestamp":1560941012000},"page":"569","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Frequency of Hepatitis B Virus Resistance Mutations in Women Using Tenofovir Gel as Pre-Exposure Prophylaxis"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6033-7655","authenticated-orcid":false,"given":"Cheryl","family":"Baxter","sequence":"first","affiliation":[{"name":"Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Private Bag X7, Congella, 4013, Durban, South Africa"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9625-8131","authenticated-orcid":false,"given":"Sinaye","family":"Ngcapu","sequence":"additional","affiliation":[{"name":"Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Private Bag X7, Congella, 4013, Durban, South Africa"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jason T","family":"Blackard","sequence":"additional","affiliation":[{"name":"Division of Digestive Diseases, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eleanor A","family":"Powell","sequence":"additional","affiliation":[{"name":"Division of Digestive Diseases, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Patricia K","family":"Penton","sequence":"additional","affiliation":[{"name":"Division of Digestive Diseases, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Salim S","family":"Abdool Karim","sequence":"additional","affiliation":[{"name":"Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Private Bag X7, Congella, 4013, Durban, South Africa"},{"name":"Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,6,19]]},"reference":[{"key":"ref_1","unstructured":"World Health Organisation (2017). 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