A prospective, randomised study on the use of well-fitting masks for prevention of invasive aspergillosis in high-risk patients.

The problem of inhalation of Aspergillus spores outside rooms with high-efficiency particulate air (HEPA) filtration has not been resolved as yet. Well-fitting masks are used in industrial and health care settings to protect from inhaling particles of 0.3-0.5 mum size. To investigate the efficacy and tolerability of well-fitting masks in high-risk patients, we conducted a prospective, randomised, multicentre study comparing standard hospital hygiene procedures with or without wearing masks in adults undergoing chemotherapy for acute leukaemia or allogeneic haematopoietic stem-cell transplantation (aHSCT). Forty-one patients were randomly assigned to wearing masks and 39 to the control group. In all, 76% of patients were treated in laminar airflow or HEPA-filtered rooms, 84% received oral polyenes, and three aHSCT recipients were given fluconazole. Duration of neutropenia was similar in both treatment groups. Invasive fungal infections were diagnosed in eight patients in either study arm. One patient in each arm died from proven invasive aspergillosis. There was no difference in the use of systemic antifungals. Of patients in the mask group, 65% described the comfort as acceptable, 26% as unpleasant, and 9% as intolerable. This first randomised study on the use of well-fitting masks failed to show a reduction of invasive fungal infections.