Candidemia and Fungal Infections in COVID-19 Patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been accompanied by a marked increase in secondary fungal infections, notably candidemia, an invasive bloodstream infection caused by Candida species. Critically ill COVID-19 patients often require prolonged intensive care, broad-spectrum antimicrobial therapy and indwelling central venous catheters, all of which predispose to candidemia. Immune dysregulation associated with COVID-19, including aberrant cytokine release and lymphocyte dysfunction, further undermines host defence against fungal pathogens. Globally, the incidence of Candida bloodstream infections in COVID-19 cohorts has ranged from around 1 % to over 5 %, with non-albicans species such as C. parapsilosis and the emerging C. auris increasingly implicated. These infections carry high mortality, prolonged hospital stay and substantial resource utilisation. Antifungal resistance—particularly to fluconazole—has been observed with rising frequency, highlighting the need for early diagnosis, targeted prophylaxis in high-risk patients and stewardship of existing antifungal agents. Understanding the epidemiology, risk factors and immunopathology of candidemia in the context of COVID-19 is essential to inform clinical monitoring, optimise therapeutic strategies and curb nosocomial transmission.

Research from Nature Portfolio

A comprehensive nationwide analysis of hospitalised COVID-19 patients in Spain during 2020–2021 reported a 1.41 % incidence of healthcare-associated fungal co-infections. Key risk factors included surgical procedures, sepsis, advanced age, male gender, obesity and chronic obstructive pulmonary disease. Patients with documented fungal co-infections experienced significantly higher in-hospital and intensive-care mortality rates, as well as extended length of stay. Candida spp. and Aspergillus spp. accounted for the majority of isolations, with surgery emerging as an independent risk factor for Aspergillus coinfection. This large-scale study emphasises the substantial impact of fungal complicatio­ns on COVID-19 outcomes and underscores the importance of preventive strategies in at-risk populations.

Candidemia and Fungal Infections in COVID-19 Patients publication trend

The graph below shows the total number of articles in candidemia and fungal infections in covid-19 patients across all publications each year (not limited to Nature Index journals).

Technical terms

Candidemia: Invasive bloodstream infection caused by Candida species, leading to systemic dissemination and high mortality if untreated.

Fluconazole resistance: Reduced susceptibility of Candida isolates to the azole antifungal fluconazole, often requiring alternative therapies.

Echinocandins: A class of antifungal agents that inhibit fungal cell-wall β-1,3-D-glucan synthesis, used as first-line treatment for invasive candidiasis.

Central venous catheter (CVC): A long, flexible tube inserted into a large vein for administration of medications or nutrition, known to be a risk factor for bloodstream infections.

Total parenteral nutrition (TPN): Intravenous administration of complete nutritional formulas, which increases the risk of catheter-related candidemia.

References

1. Increase in candidemia cases and emergence of fluconazole-resistant Candida parapsilosis and C. auris isolates in a tertiary care academic hospital during the COVID-19 pandemic, Greece, 2020 to 2023. Eurosurveillance (2024).
2. Epidemiology of fungal infection in COVID 19 in Spain during 2020 and 2021: a nationwide study. Scientific Reports (2024).
3. Candidemia in critically ill COVID-19 patients: Risk factors and impact on mortality. Heliyon (2024).
4. Yeast Bloodstream Infections in the COVID-19 Patient: A Multicenter Italian Study (FiCoV Study). Journal of Fungi (2023).
5. COVID-19 Impairs Immune Response to Candida albicans. Frontiers in Immunology (2021).