Bacterial and viral co-infections in adult patients hospitalized with COVID-19 throughout the pandemic: A Multinational Cohort Study in the EuCARE Project.

Hedberg P, Serwin K, Francesca Greco M, Pereira JPV, Juozapaite D, De Benedittis S, Bai F, Lübke N, Wienemann T, Fanti I, König F, Pfeifer N, Kaiser R, Zazzi M, Cozzi-Lepri A, Naumovas D, Marchetti G, Parczewski M, Jensen BO, Incardona F, Sönnerborg A, Nauclér P

The Journal of Infectious Diseases - (-) - [2025-04-03; online 2025-04-03]

Limited evidence exists on how the occurrence of bacterial and viral co-infections have developed since the SARS-CoV-2 Omicron variant emerged. We investigated whether the occurrence of community-onset co-infections in adult patients hospitalized with COVID-19 differed during the Wild type, Alpha, Delta, and Omicron periods, and whether such co-infections were associated with an increased risk of mortality. We conducted a multinational cohort study including COVID-19 hospitalizations until 30 April 2023 in five European countries. The outcome was bacterial and viral co-infections, based on five different test modalities. Variant periods were compared with regards to occurrences of co-infections and risk ratios for co-infections (Omicron versus pre-Omicron), as well as association with in-hospital mortality (Omicron versus pre-Omicron). A total of 29,564 patients were included: 12,601 Wild type, 5,256 Alpha, 2,433 Delta, and 9,274 Omicron. The co-infection rate was 2.6% (327/12,601) for Wild type, 2.0% (105/5,256) for Alpha, 3.2% (77/2,433) for Delta, and 7.9% (737/9,274) for Omicron. Patients with Omicron had a significantly increased risk ratio of co-infection compared with preceding variants (1.88 [95% CI 1.53-2.32], P<0.001). These results were consistent across several subgroup analyses. An increased occurrence (19% [232/1,246] versus 11% [3,042/28,318]) and adjusted risk (1.69 [1.49-1.91], P<0.001) of in-hospital mortality was observed in patients with a verified co-infection compared with patients without a co-infection. Bacterial and viral co-infections were more prevalent during the Omicron period compared with preceding variants. Such co-infections were associated with an increased risk of in-hospital mortality, calling for sustained monitoring and clinical vigilance.

PubMed 40176475

DOI 10.1093/infdis/jiaf167

Crossref 10.1093/infdis/jiaf167

pii: 8104499