Background: Clinical guidelines and policies often fail to achieve high levels of delivery of intended clinical interventions. The difference in what the investigators know works and what is actually delivered at the clinic-level to patients, is known as the science-to-service gap. In the realm of tuberculosis (TB) prevention, this gap is reflected in \<20% of TB preventive therapy (TPT) -eligible persons living with HIV (PWH) being offered or initiated on isoniazid preventive therapy (IPT) in many settings. Recent innovation in TPT have brought new pharmacological options allowing for shorter courses, intermittent dosing, or both. The overarching goal of this study is to identify a generalizable approach to overcome current barriers to delivery of TPT in order to achieve high levels of TPT delivery during routine care in public clinics. Multiple approaches are in standard use to change prescribing behavior including in service training, audit and feedback, clinical mentoring, the use of clinical decision aids, and academic detailing. However, the overall change is generally modest. To achieve a substantial increase in TPT delivery (from current approximately 20% to 60-80%) will require a fundamental change in the approach to selecting patients for TPT - a redesign of the choice architecture of TPT prescribing.

Methods: The investigators are proposing a choice architecture that makes prescribing TPT the default or standard option and that for TPT not to be prescribed will require a choice by a clinician to opt-out of TPT for a specific patient. The investigators are proposing a cluster randomized design to test the choice architecture approach to increasing delivery of TPT. Clinics will be randomized to one of two strategies: (1) standard implementation and (2) choice architecture default TPT. Because of the clinic-level nature of the implementation strategies, all PWH receiving care at a clinic will be exposed to the standard implementation or TPT routinization implementation. Clinical process data will be used to assess the effectiveness of each strategy to determine the proportion of PWH (1) screened for TPT, (2) eligible for TPT, and (3) prescribed TPT. Significance: TB is the leading cause of death among PWH in South Africa and elsewhere on the continent. TPT is a proven intervention to reduce mortality among PWH but is not widely prescribed. This study seeks to identify an implementation strategy to reach optimal TPT prescribing.