Clinical Characteristics and Outcomes of Invasive Pulmonary Aspergillosis in Patients with Influenza Compared to COVID-19: A Retrospective Cohort Analysis

By
Renwen Zhang
Jun Liu
Ran Li
Li Gu
April 24, 2026
0 min

Frontiers In Medicine

Overview

This retrospective cohort study compared invasive pulmonary aspergillosis (IPA) in patients with influenza (IAPA) and COVID-19 (CAPA). CAPA patients exhibited more severe lymphopenia, higher corticosteroid use, more bacterial co-infections, and a nearly five-fold increased risk of death within 14 days after IPA diagnosis compared to IAPA patients.

Background

Invasive pulmonary aspergillosis (IPA) is a serious complication in patients with severe viral pneumonia caused by influenza or COVID-19. Both viral infections cause pulmonary inflammation and immune dysregulation, predisposing patients to fungal co-infections. While IAPA and CAPA have been recognized separately, direct comparisons of their clinical features and outcomes remain limited. Understanding differences between these entities is critical for optimizing diagnosis and management strategies.

Data Highlights

Characteristic	IAPA (n=45)	CAPA (n=82)	p-value
Lymphocyte counts (CD4+, CD8+, B cells)	Higher	Significantly lower	<0.05
Corticosteroid use	Less frequent	More frequent	Not specified
Median time from viral diagnosis to IPA detection	Shorter	Longer	Not specified
Respiratory bacterial co-infections	Less common	More common	0.030
Risk of death within 14 days post-IPA diagnosis (HR)	Reference	4.92 (95% CI: 1.35–18.01)	0.016

Key Findings

CAPA patients had significantly lower lymphocyte subsets (CD4+, CD8+, B cells) compared to IAPA patients (p < 0.05).
Corticosteroid therapy was more commonly used in CAPA patients than in IAPA patients.
The median interval from viral diagnosis to IPA detection was longer in CAPA than in IAPA.
Bacterial respiratory co-infections occurred more frequently in CAPA patients (p = 0.030).
After adjustment, CAPA was associated with a 4.92-fold increased hazard of death within 14 days following IPA diagnosis (p = 0.016).

Clinical Implications

Clinicians should recognize that CAPA patients are at higher risk of early mortality and often present with severe lymphopenia and bacterial co-infections. Early identification and prompt antifungal and supportive therapies, especially within the first two weeks after IPA diagnosis, are critical. The higher corticosteroid use in CAPA patients warrants careful monitoring to balance immunosuppression risks.

Conclusion

CAPA differs from IAPA by exhibiting more profound immunosuppression, increased bacterial co-infections, and a markedly higher early mortality risk. These findings highlight the need for heightened clinical vigilance and early therapeutic intervention in CAPA patients.

References

Study Authors/Beijing Chaoyang Hospital/2024 -- Clinical Characteristics and Outcomes of Invasive Pulmonary Aspergillosis in Patients with Influenza Compared to COVID-19