Funding for this research was provided by:
National Institute of Allergy and Infectious Diseases (AI36214, AI07384)
National Institute on Drug Abuse (DA24998)
California HIV/AIDS Research Program (F06-SD-258)
National Institute of Nursing Research (NR10961)
National Institute for Health Research (CDF-2011-04-017)
Clinical Research Council (UK-CRC G0800777)
Received: 12 April 2017
Accepted: 1 February 2018
First Online: 7 February 2018
Ethics approval and consent to participate
: All participants completed verbal and documented anonymous (by a check box in the computer-assisted self-interview) informed consent prior to participation. The use of cash for compensation and the waiver of written consent was intended to increase anonymity of participants. Although the interviews were self-administered, a member of the research team was on hand to answer any questions. The research protocol was approved by the University of California, San Diego Institutional Review Board, including the use of verbal consent only.
: No details related to any given individual are included in the manuscript. All results are presented in aggregate, and consent to publish is not required.
: The authors declare that they have no competing interests.
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