Construction Season: How to Protect Immunocompromised Patients from Aspergillus During Renovations

Every hospital construction and renovation project represents a potential threat to the most vulnerable patients in the facility. Aspergillus fumigatus and other environmental moulds — ubiquitous in soil, decaying vegetation, and building materials — are mobilised in large quantities when walls are demolished, ceilings disturbed, or air handling systems disrupted. For immunocompromised patients, particularly those undergoing haematopoietic stem cell transplantation or receiving intensive chemotherapy, inhalation of even a small number of Aspergillus conidia can cause invasive pulmonary aspergillosis — a condition with mortality rates of 30–90% in the most immunosuppressed patients.

The Infection Control Risk Assessment (ICRA) is the systematic framework used to evaluate infection risks associated with construction, renovation, and maintenance activities in healthcare facilities, and to implement proportionate control measures before, during, and after the project.

The ICRA Process

The ICRA involves two matrices: (1) Patient risk group — from low risk (general medicine patients) to highest risk (allogeneic HSCT recipients); (2) Construction activity type — from Type A (minor maintenance without dust) to Type D (major demolition generating significant dust). The intersection of these two matrices determines the required infection control class (Class I through IV) and the specific barrier and monitoring requirements. For the highest-risk combination, requirements include: full dust barriers from floor to ceiling, sealed with tape; negative pressure within the construction zone maintained at all times; HEPA-filtered air supplied to the construction area; patient relocation from adjacent areas if barriers cannot be fully maintained; and daily monitoring of construction zone air pressure differentials.