This IHEEM Briefing Note has been prepared by the Ventilation Technical Platform (VTP) to highlight a potentially serious emerging issue relating to an increasing occurrence of a co-infection risk from aspergillus in patients with severe COVID-19 infections. It is intended to remind all estates professionals who are involved in the management, maintenance or project schemes of the requirement to ensure an adequate and appropriate risk assessment has been undertaken in line with the requirements of HBN 00-09 ‘Infection control in the built environment’, and to ensure suitable mitigation or controls are in place to protect patients as far as is reasonably practicable.