Situation: The occupational health nurse of a private garment factory with 800 workers, including a fabric-dyeing area, is reviewing the workplace health and safety program. The nurse sorts the factory's health activities by level of prevention. Which activity is TERTIARY prevention?

Tertiary prevention acts after disease or injury has occurred; it limits disability and restores function through rehabilitation. Modified duty and return-to-work programs let an injured worker resume work safely while recovering. Vaccination and noise enclosures prevent disease from starting (primary), and periodic audiometry detects early hearing loss (secondary).

Levels of Prevention in Occupational Health

The occupational health nurse categorizes workplace activities according to when they occur in relation to disease or injury. Tertiary prevention is implemented after a condition has already developed, with the goal of limiting disability, restoring function, and supporting safe reintegration into work. In this scenario, the worker has already sustained a back injury, so any intervention aimed at helping that worker recover and return to productive activity falls under tertiary prevention.

Modified duty is a classic tertiary prevention strategy. It involves temporarily adjusting job tasks, hours, or physical demands so an injured employee can resume work while still healing. The purpose is not to prevent the original injury, but to prevent worsening of the existing condition, avoid prolonged disability, and facilitate rehabilitation through graded activity. Return-to-work programs that incorporate modified duty are recognized as effective approaches for reducing disability duration and improving functional outcomes after work-related injuries. Studies of workers with upper extremity disorders show that returning to modified duty can ease the transition back to normal work activities ^[1]. Similarly, modified work programs that provide a gradual increase in workload are a core component of disability management for musculoskeletal conditions such as low back pain ^[3].

The other options represent earlier levels of prevention. Hepatitis B vaccination and noise enclosures are primary prevention because they aim to prevent disease or injury from occurring in the first place. Periodic hearing tests are secondary prevention because they screen for early, asymptomatic hearing loss so that intervention can begin before significant damage progresses.

Prevention Level	Timing	Goal	Example from Scenario
Primary	Before disease or injury occurs	Prevent onset	Hepatitis B vaccination, noise enclosures around looms
Secondary	Early, often asymptomatic stage	Detect disease early; prompt treatment	Periodic hearing tests for weaving area workers
Tertiary	After disease or injury has occurred	Limit disability; restore function; rehabilitation	Modified duty for a worker healing from a back injury

Key point! The timing of the intervention relative to the health problem determines the level of prevention. If the injury already exists and the intervention helps the person manage or recover from it, it is tertiary prevention.

Watch out! Do not confuse modified duty with ergonomic redesign of workstations. Ergonomic changes made before an injury occurs are primary prevention; modified duty is applied after an injury has already happened. Workplace accommodation research indicates that modifying ergonomic risk factors can reduce recurrent pain and improve return-to-work outcomes, but the accommodation itself is a tertiary intervention when it follows an existing injury . Interdisciplinary occupational health approaches that embed rehabilitation and accommodation strategies have also been associated with faster return-to-work times after musculoskeletal injuries, reinforcing the value of tertiary prevention in occupational settings .