The purpose of this trial is to test the effectiveness of offering a menu of different tobacco smoking substitutional products (e-cigarettes, nicotine pouches, nicotine patches in addition to usual of care) for smokers in the SHCS (Swiss HIV Cohort Study) in achieving self-reported 7-day tobacco cigarette abstinence at 6 months.

Due to highly effective antiretroviral therapy, people living with HIV (PLWH) in Switzerland have a close-to-normal life expectancy. Among PLWH, there has been a shift of focus from HIV-related health issues to non communicable diseases, especially cardiovascular diseases (CVDs) and cancer. Smoking, a prominent risk factor for both diseases, takes a key role in view of the high number of smokers among PLWH.

New approaches to smoking cessation focus on harm reduction by substituting tobacco cigarettes by less harmful alternatives. Conventional nicotine replacement therapy like nicotine patches is well established and effective against withdrawal symptoms after quitting. However, these products are exceptionally expensive and the missing "nicotine hit" often limits therapy adherence. The long-term abstinence rate remains low. Electronic cigarettes (e-cigarettes) and nicotine pouches as alternative nicotine replacement therapies have the potential to overcome these problems and are accessible.

E-cigarettes play a growing role in smoking cessation therapy. Evidence from randomized trials shows superiority over conventional nicotine replacement therapies, which is probably based on the better imitation of the smoking experience. Although e-cigarettes are not without concerns, there is consensus that they are significantly less harmful than tobacco cigarettes.

Tobacco-free nicotine pouches, delivering nicotine through oral mucosa, are a relatively novel option for nicotine substitution. Similar to e-cigarettes, nicotine pouches are relatively affordable and can address the limitation of poor imitation of the "nicotine hit" seen with traditional nicotine replacement therapy. To the best of our knowledge, no trials have investigated the potential of nicotine pouches for smoking cessation so far.

With this trial, the investigators also want to address frequent shortcomings of smoking cessation trials, such as restrictive inclusion criteria and highly controlled interventions, by RETUNE Version 1.1, January 06, 2025 10/45 offering a menu of different tobacco smoking substitutional products (e-cigarettes or nicotine pouches or nicotine patches) and by using a novel pragmatic trial design, the Trials within Cohorts (TwiCs) design. The investigators plan to recruit tobacco smokers in the Swiss HIV Cohort Study (SHCS), regardless of their willingness to quit. This so called "opt-out-approach" has been suggested as a new promising approach for smoking cessation trials to increase generalizability of the results. The TwiCs design optimally allows to implement and evaluate the "opt-out" approach embedded in the SHCS.

Inclusion Criteria:

• Signed informed consent for the data collection and participation in the SHCS (Cohort consent).
• Signed informed consent to be randomized to future interventions (Randomization consent).
• Age 18 years or older.
• Smoked one or more tobacco cigarettes per day (smoking status = yes) at the time of enrolment.

Exclusion Criteria:

• Currently using e-cigarettes or nicotine pouches or nicotine patches.
• Pregnant women.