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Seroconversion on preexposure prophylaxis: a case report with segmental hair analysis for timed adherence determination

Thaden, Joshua, T.a; Gandhi, Monicab; Okochi, Hideakib; Hurt, Christopher, B.c; McKellar, Mehri, S.a

doi: 10.1097/QAD.0000000000001825

Objective: We describe the third case report of seroconversion with multidrug resistant (MDR)-HIV despite pre-exposure prophylaxis (PrEP) with emtricitabine (FTC) and tenofovir (TFV) disoproxil (TDF).

Design: Case report.

Methods: PrEP adherence was assessed via self-report, pharmacy records, and measuring TFV/FTC levels with liquid-chromatography/tandem-mass-spectrometry in plasma and hair. Segmental hair analysis was performed to assess PrEP adherence over prior months. Genotypic resistance was assessed.

Results: A 34 year-old white MSM started daily FTC/TDF in February 2016 after being provided 11 refills. In March 2017, he developed fevers, chills, myalgias and was assessed, but no HIV test was sent. In April 2017, an antigen/antibody HIV test was reactive (day 0). On day 2, HIV-1 RNA was 27 316 copies/ml, genotyping revealed M184V, K70T, K65R, and K103N mutations, plasma TFV and FTC concentrations were consistent with recent dosing. To evaluate adherence over preceding months, a hair sample was collected at day 27 and segmental analysis of TFV/FTC levels performed in one-centimeter segments from the scalp. Hair drug levels (0.0434–0.0520 ng TFV/mg hair) were commensurate with consistently high PrEP adherence over the prior 3 months.

Conclusions: This study employs segmental analysis of PrEP drug levels in hair for the first time to assess adherence over preceding months in the setting of an HIV seroconversion on PrEP. High adherence over the period of likely acquisition makes MDR-HIV infection the most likely scenario in this case. Adequate adherence assessment when examining PrEP failures and ensuring best practices in PrEP prescribing and follow-up are important.

aDivision of Infectious Diseases, Department of Medicine, Duke University, Durham, North Carolina

bDivision of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California

cInstitute for Global Health & Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

Correspondence to Monica Gandhi, MD, MPH, Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF; San Francisco, CA 94112, USA. Tel: +1 415 476 4082; e-mail:

Received 23 March, 2018

Revised 6 April, 2018

Accepted 10 April, 2018

Copyright © 2018 Wolters Kluwer Health, Inc.