From Peer Support to Program Supervision: Qualitative Insights on WhatsApp as Informal Digital Infrastructure for Community Health Workers and Public Health Officers in an Indian High-Priority Aspirational District.

: In low-resource health systems, official mHealth platforms often face usability and infrastructure barriers. In India, Community Health Workers (CHWs) and their supervisors have pragmatically turned to WhatsApp as an informal digital infrastructure. While widely adopted, its dual role as both a support system and a source of burden remains underexplored. : To examine the patterns and purposes of WhatsApp use among CHWs and block-level supervisors; to identify perceived benefits, barriers, and risks; and to assess its influence on workflow, power relations, digital equity, and program outcomes in an Indian Aspirational District. : We conducted a qualitative study between June and December 2023 in Muzaffarpur, Bihar, India. Data comprised 32 in-depth interviews and six focus group discussions with CHWs (Anganwadi Workers, ASHAs, ANMs) and block-level public health officers (total participants = 81). We used reflexive thematic analysis following Braun and Clarke's approach; reporting adhered to the COREQ guideline. : WhatsApp emerged as a de facto digital backbone for real-time communication, peer support, and program supervision, often perceived as more usable than official applications. Its informal adoption also created a triple burden: digital fatigue from information overload and blurred work-life boundaries; duplication of reporting across WhatsApp and official portals; and systemic inequities that disadvantaged older or less digitally literate CHWs, with risks of surveillance creep and data privacy breaches. WhatsApp simultaneously enables coordination and imposes workload and equity costs on India's frontline workforce. Without formal policy and governance, this user-driven adaptation risks widening digital divides and accelerating burnout. We recommend clear protocols on purpose-limited use, investments in equitable digital capability and devices, and safeguards that protect worker well-being and data privacy.