The investigators broadly aim at determining barriers and facilitators to PrEP uptake and adherence and retention among the study participants. The investigators have the following specific objectives of determining: (1) the PrEP knowledge levels, attitudes, practices, and user experiences among injecting and sexual partners of PWID in Nairobi County (2) the socio-demographic, behavioural, and structural factors hindering the uptake of PrEP among PWID's sexual and injecting partners in Nairobi County; and (3) the effect of a theory-guided behavioural intervention (PrEP-UP) utilizing peer outreach and navigation on the uptake of PrEP by the study participants.

The investigators hypothesize that: PWID's injecting and sexual partners in Nairobi City lack PrEP knowledge, and have poor attitudes practices, and user experiences about PrEP; less than 50.0% of the PWID's sexual and injecting partners in Nairobi County have socio-demographic, behavioural and structural factors hindering their uptake of PrEP; and a theory-guided behavioural intervention (PrEP-UP) utilizing peer outreach and navigation has no effect on the uptake of PrEP by the study participants.

Background: The annual global number of new HIV infections among adults has remained unchanged over the last decade and it is largely fuelled by key populations among them people who inject drugs (PWID). Key populations in Kenya account for one-third of all new HIV infections and 18.3% of PWID in the country are living with HIV. Drug and substance use is on the increase in the country, with close to 4 out of 10 Kenyans reporting to have used a substance in their lifetime including injectable drugs thus fueling the spread of HIV. Pre-Exposure Prophylaxis (PrEP) is effective in the prevention of HIV transmission among PWID by over 70.0% if and when used correctly. However, uptake, adherence, scale-up of use, coverage and retention currently remain limited. Thus, effective interventions are needed to enhance the uptake of PrEP among PWID and their sexual and injecting partners in order to prevent HIV transmission.

Objectives of the Study: Broadly, the investigators aim at determining PrEP uptake barriers and facilitators and adherence among the study participants and the sequel of a theory-guided behavioral intervention model (PrEP-UP) on the uptake of PrEP by the study participants. Specifically, the investigators aim at determining: (1) the PrEP knowledge levels, attitudes, practices and user experiences among the study participants(2) the socio-demographic, behavioural and structural factors hindering the uptake of PrEP among the study participants; and (3) the effect of a theory-guided behavioural intervention (PrEP-UP) utilizing peer outreach and navigation on the uptake of PrEP by the study participants.

Methods: The investigators will conduct the study for twelve months (1st July 2021 to 30th June 2022) and they will use an implementation study through a pre-post design to assess 256 participants' self-reported PrEP uptake and retention before and after exposure to a theory-guided behavioural intervention (PrEP-UP) utilizing navigators and peer outreach for the 128 'cases' and PrEP information Pamphlet and list of health facilities offering PrEP for free in Nairobi County for the 128 'control' group members. The investigators will use four study sites namely Githurai, Kawangware, Ngara and Pangani PWID's hotspots within Nairobi City. The targeted study participants are PWID's sexual and injecting partners of ages 18 years and above. The investigators will recruit 256 study participants into the study by use of peers and social workers in the University of Washington's Needle and Syringe Program (NSP) sites in Githurai, Kawangware, Ngara and Pangani. The investigators will collect baseline data after recruitment while the interventions for both groups will be offered in a maximum 5 contact sessions with investigators and a follow-up of the participants will be done by the investigators at weeks 4, 8 and 12 to establish whether study participants have taken up PrEP by week 12 during which post-intervention data will be collected. Lastly, participants' self-reported PrEP retention will be documented by investigators at 18 weeks and HIV tests will be conducted on the participants by the investigators (optional) through OraQuick antibody HIV tests. The investigators will analyze: quantitative data through the Statistical Package for Social Sciences (SPSS) version 24 and: qualitative data through flow chart matrices to establish divergence and convergence of themes.

Significance of the Study: Through the study, the investigators will contribute to the global call for the reduction in new HIV infections among PWIDs and their sexual and injecting partners. The study will further inform the investigators on the effectiveness-implementation science interventions and recommend the best PrEP scale-up approaches in addition to contributing to the global scientific knowledge.

The inclusion criteria for the study includes:

Being age 18 years and above.

Being HIV negative on a rapid HIV test conducted prior to interviews.

No pregnancy for females at the time of recruitment.

Active injection of illicit drugs in the six months preceding the study.

High multiple HIV risk and high HIV through sexual activities and sharing of injection equipment or syringes (the high multiple-risk group mixed unsafe drug use with unsafe sexual practices; the second group practiced high-risk sex with non-consistent condom combined with drug use; the moderate-risk group had limited unsafe sexual practices; and the "low-risk" group never had unprotected sex and never shared needles and other injection equipment).

Informed consent to participate inti the study.

The exclusion criteria includes:

Being a minor (below 18 years).

Those not actively injecting drugs.

Acute or chronic HIV infection

Those not consenting to participation into the study.

Pregnancy.

Cases : Navigation into PrEP

Control group: Provision of pamphlets with information on PrEP.