Hand hygiene among Nigerian university students: opportunity constraints and micro-context variability interpreted through the COM-B framework

Hand hygiene is a low-cost cornerstone of infection prevention, yet adherence among undergraduates in low- and middle-income countries (LMICs) is often inconsistent due to structural and time-related constraints. This study described knowledge, attitudes and self-reported hand hygiene practices among undergraduates at a Nigerian university, and examined how water access, facility placement and time scarcity relate to practice. Patterns were interpreted through the Capability–Opportunity–Motivation–Behaviour (COM-B) framework to identify opportunity-focused levers for LMIC-university systems. Among 420 respondents (99.5% response rate), mean knowledge and attitude scores were high (10.8/14 and 13.2/16). However, only 41.9% met the composite definition of good practice (always washing after toilet use and before eating, and ≥ 20 s per wash). “Always” washing ranged from 79.8% after toilet use to 10.2% before buying food from canteens. In multivariable analysis, higher knowledge (aOR 1.35, 95% CI 1.10–1.65), higher attitude scores (1.20, 1.02–1.42), reliable water access (1.80, 1.15–2.82) and facility proximity (1.55, 1.02–2.35) independently predicted good practice, while frequent post-class time constraints reduced the odds (0.60, 0.40–0.90). Interpreted through COM-B, capability and motivation were relatively strong, while physical opportunity—WASH access, facility placement and protected time—appeared to be the limiting component.