To determine the incidence and characteristics of superinfections in mechanically ventilated COVID-19 patients, and the impact of dexamethasone as standard therapy.

This multicentre, observational, retrospective study included patients ≥ 18 years admitted from March 1^st 2020 to January 31^st 2021 with COVID-19 infection who received mechanical ventilation. Patient characteristics, clinical characteristics, therapy and survival were examined.

155/156 patients (115 men, mean age 62 years, range 26-84 years) were included. 67 patients (43%) had 90 superinfections, pneumonia dominated (78%). Superinfections were associated with receiving dexamethasone (66% vs 32%, p<0.0001), autoimmune disease (18% vs 5.7%, p<0.016) and with longer ICU stays (26 vs 17 days, p<0,001). Invasive fungal infections were reported exclusively in dexamethasone-treated patients [8/67 (12%) vs 0/88 (0%), p<0.0001]. Unadjusted 90-day survival did not differ between patients with or without superinfections (64% vs 73%, p=0.25), but was lower in patients receiving dexamethasone versus not (58% vs 78%, p=0.007). In multiple regression analysis, superinfection was associated with dexamethasone use [OR 3.7 (1.80–7.61), p<0.001], pre-existing autoimmune disease [OR 3.82 (1.13–12.9), p=0.031] and length of ICU stay [OR 1.05 p<0.001].

In critically ill COVID-19 patients, dexamethasone as standard of care was strongly and independently associated with superinfections.