The single greatest health behavior change that could improve cardiovascular morbidity and associated mortality is to assist people living with HIV/AIDS who smoke to quit. The investigators will use a factorial design to evaluate the most promising behavioral and pharmacologic treatments aimed at achieving maximal efficacy for smoking cessation among people living with HIV/AIDS who smoke. Results of this study will provide crucial, real world evidence of the best way for healthcare providers to help smokers living with HIV/AIDS quit smoking.

The study used a factorial design to randomize participants into 4 conditions: (1) Varenicline (12 weeks) + Positively Smoke Free (PSF) (8 weeks); (2) Varenicline (12 weeks) + Standard of Care (brief advice to quit); (3) Placebo (12 weeks) + Positively Smoke Free (8 weeks); and (4) Placebo (12 weeks) + Standard of Care. The primary outcome was the 7-day point prevalence abstinence (PPA) (<10mm) at 36 weeks.

The specific aims of our proposal are:

Primary Aim 1: Compare varenicline to placebo on rates of 7-day point prevalence abstinence (PPA) at 36 weeks in smokers with HIV/AIDS. We hypothesize that rates of smoking abstinence at week 36 will be higher in those treated with varenicline compared to placebo.

Primary Aim 2: Compare Positively Smoke Free to low intensity, brief counseling on rates of 7-day PPA at 36 weeks in smokers with HIV/AIDS. We hypothesize that rates of smoking abstinence at week 36 will be higher in those treated with Positively Smoke Free compared to brief counseling.

Primary Aim 3: Compare Positively Smoke Free + varenicline to the other two study conditions outlined above on rates of 7-day PPA in smokers with HIV/AIDS at 36 weeks. We hypothesize the effect of PSF with varenicline is greater than the effect of PSF or varenicline alone.

Exporatory Aim: Explore the effect of successful cessation/smoking abstinence on levels of cardiac specific biomarkers, nicotine biomarkers, generalized markers of inflammation, lipids, coagulation and monocyte/macrophage activation.

Study Inclusion Criteria:

1. Confirmed chart diagnosis of a HIV and receiving HIV treatment at the participating HIV clinic.
2. Age 18 years or older.
3. Currently self-report smoking 10 cigarettes per day
4. Motivation to quit within the next 6 months (score 5-8 on the Abrams and Briener Readiness to Quit Ladder);
5. Does not meet criteria for current Diagnostic Statistical Manual (DSM) 5 moderate or severe alcohol use disorder or moderate or severe substance use disorder as established by the Mini Neuropsychiatric Interview (MINI) drug and alcohol sections (in the last 3 months)
6. Able to read and speak English
7. Willingness and ability to provide informed consent to participate.

Study Exclusion Criteria:

The exclusion criteria are designed to maximize safety by minimizing drug interactions or worsening pre-existing comorbid psychiatric or medical conditions:

1. Current suicidal thoughts or ideation (past week); recent suicidal thoughts or ideation (past 6 months) or recent suicide attempt (past 6 months) as assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS).
2. Previous allergic reaction or hypersensitivity to Varenicline (by participant report ever in lifetime)
3. Pregnant, nursing, or becoming pregnant during the study (pregnancy test).
4. Current use of any medication that would interfere with the protocol in the opinion of Medically Accountable Physician including use of bupropion targeting nicotine dependence
5. Moderate to severe renal impairment (< 30 mL/min)--As determined by a physician assessment, chart review or thru blood work
6. Unstable cardiovascular disease (myocardial infarction within past year, uncontrolled arrhythmia, uncontrolled angina, uncontrolled congestive heart failure, electrocardiogram abnormality with QTC > 500 msec, cerebrovascular event within past year). (As determined by a physician assessment, chart review and/or EKG)
7. Meets criteria for dementia by scoring below 10 on the Hopkins HIV Dementia Scale. This criterion is included to ensure the sample consists of participants who are cognitively able to engage in the study procedures
8. Scores <5 ppm of expired carbon monoxide (CO) on the Smokelyzer
9. The study physician believes that the individual is not medially stable enough to participate in the study. This exclusion will be based on a review of the individual's past medical history and current medical status.
10. Recent use of Varenicline (by participant report in the past 3 months)

12 weeks--This is the timeframe for the medication related non-serious adverse events as the medication part of the trial was discontinued after 12 weeks. 36 weeks--This is the timeframe for all cause mortality and serious adverse events

All-Cause Mortality: All anticipated and unanticipated deaths due to any cause Serious Adverse Events: All anticipated and unanticipated serious adverse events Other (Not Including Serious) Adverse Events: Anticipated and unanticipated events that exceed a frequency threshold (maximum threshold, 5%) within any arm of the clinical study, grouped by organ system, with number and frequency of such events in each arm/group of the clinical study.

From March 16, 2020-August 10, 2020 study recruitment was halted due to COVID-19.