Prior Influenza Infection Mitigates SARS-CoV-2 Disease in Syrian Hamsters
Caterina Di Pietro1, Ann M Haberman2, Brett D Lindenbach3,4
1Department of Pediatrics, Yale School of Medicine, New Haven, CT 06519, USA.
Viruses
|February 24, 2024
Summary
Influenza A virus infection prior to SARS-CoV-2 significantly reduced COVID-19 severity in hamsters. This early flu infection boosted innate immunity, decreasing SARS-CoV-2 viral load and lung inflammation.
Area of Science:
- Virology
- Immunology
- Respiratory Medicine
Background:
- Seasonal respiratory virus infections, including SARS-CoV-2 and influenza, often overlap.
- Interactions between concurrent viral infections can modulate disease severity and epidemiological patterns.
Purpose of the Study:
- To investigate the immunopathologic interactions between influenza A virus (H1N1pdm09) and SARS-CoV-2.
- To determine if prior H1N1 infection influences SARS-CoV-2 pathogenesis.
Main Methods:
- Syrian hamsters were infected with H1N1 48 hours before SARS-CoV-2 challenge.
- Evaluated clinical signs, lung pathology, immune cell dynamics (granulocytes, antigen-presenting cells), and nasal transcriptomics.
- Quantified viral loads and cytokine levels using RT-PCR.
Main Results:
- Prior H1N1 infection significantly mitigated SARS-CoV-2-induced weight loss and lung pathology.
- H1N1 inoculation accelerated immune cell responses and upregulated innate antiviral pathways.
- Dual infection led to decreased SARS-CoV-2 viral load and lower pro-inflammatory cytokine levels in the lungs.
Conclusions:
- H1N1 infection induces rapid, transient gene expression that protects against severe SARS-CoV-2 pulmonary disease.
- These protective effects likely originate in the upper respiratory tract.
- Interactions between influenza and SARS-CoV-2 may impact their respective seasonal prevalence.
