Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is a global health threat with the potential to cause severe disease manifestations in the lungs. Although COVID-19 has been extensively characterized clinically, the factors distinguishing SARS-CoV-2 from other respiratory viruses are unknown. Here, we compared the clinical, histopathological, and immunological characteristics of patients with COVID-19 and pandemic influenza A(H1N1). We observed a higher frequency of respiratory symptoms, increased tissue injury markers, and a histological pattern of alveolar pneumonia in pandemic influenza A(H1N1) patients. Conversely, dry cough, gastrointestinal symptoms and interstitial lung pathology were observed in COVID-19 cases. Pandemic influenza A(H1N1) was characterized by higher levels of IL-1RA, TNF-α, CCL3, G-CSF, APRIL, sTNF-R1, sTNF-R2, sCD30, and sCD163. Meanwhile, COVID-19 displayed an immune profile distinguished by increased Th1 (IL-12, IFN-γ) and Th2 (IL-4, IL-5, IL-10, IL-13) cytokine levels, along with IL-1β, IL-6, CCL11, VEGF, TWEAK, TSLP, MMP-1, and MMP-3. Our data suggest that SARS-CoV-2 induces a dysbalanced polyfunctional inflammatory response that is different from the immune response against pandemic influenza A(H1N1). Furthermore, we demonstrated the diagnostic potential of some clinical and immune factors to differentiate both diseases. These findings might be relevant for the ongoing and future influenza seasons in the Northern Hemisphere, which are historically unique due to their convergence with the COVID-19 pandemic.
Highlights
The novel SARS-CoV-2 has submerged the world into a public health crisis of unprecedented features
The main demographic characteristics of enrolled patients were similar (Table 1), the proportion of males tended to be higher in both groups of COVID-19 subjects, as reported before [9, 11, 12, 17, 23, 24]
Rhinorrhea, sore throat, thoracic pain, and sputum production were more common during pandemic influenza A(H1N1), whereas dry cough, diarrhea, and vomit were more frequent among COVID-19 patients
Summary
The novel SARS-CoV-2 has submerged the world into a public health crisis of unprecedented features. Other emerging pathogens have caused similar outbreaks in the past, the pandemic influenza A(H1N1) pdm virus is the immediate antecedent reference for the global spread of a new zoonotic respiratory pathogen. This virus emerged in Mexico in 2009, causing approximately 151,700-575,400 deaths worldwide during the first year after its appearance [2,3,4]. The emergence of SARS-CoV-2 in December of 2019 [6,7,8], occurred when several countries were at the peak of the flu season This hampered differentiating COVID-19 and influenza during the early days of the current pandemic. With improved understanding of the clinical characteristics and pathobiology of COVID-19 [9,10,11,12], the overall identification of positive cases drastically improved
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