Invasive aspergillosis is difficult to diagnose in critically unwell patients without traditional host factors because radiological changes are usually nonspecific (e.g. infiltrates, consolidation or nodules), with features such as halo sign, air-crescent sign or cavitation being rare [24]. For these reasons Schauwvlieghe et al. [13] developed the modified AspICU criteria to help diagnose IAPA which (in the absence of histology) essentially relies on mycological evidence of Aspergillus spp. in the form of a positive bronchoalveolar lavage (BAL) culture or positive galactomannan (GM) in serum/BAL. Applying these modified AspICU criteria, five cases of CAPA in table 1 were “proven”, 11 “putative” and 17 might be considered putative but with caveats which have been described in the table. For example, in many cases a tracheal aspirate, rather than BAL, provided the only mycological evidence of invasive aspergillosis (in the absence of tracheobronchitis/cavitation). There should therefore be caution about over-estimating the incidence of CAPA from such case series, which may include some patients with aspergillus colonisation or contamination only. In the study by Alanio et al. [9] which reported evidence of CAPA in nine (33%) out of 27 ventilated patients who underwent BAL/tracheal aspirate, one case was defined based on a BAL GM of 0.89 (below the usual cut-off of 1.0), two based on tracheal aspirate rather than BAL culture, one based on a serum GM of 0.51 (cut-off being 0.50) and in four cases BAL culture was positive but BAL GM negative, which suggests a lack of tissue invasion. Indeed, out of seven cases that were not treated with antifungals, five survived. Accordingly, larger, prospective, multi-site studies are needed to refine the AspICU criteria for patients with COVID-19, as well as to estimate incidence and the impact of CAPA on survival [25, 26].