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. 2024 Oct 27;12(11):1220. doi: 10.3390/vaccines12111220

Table 1.

Comparison of influenza virus and coronavirus (SARS-CoV-2). ↓ means decreas and ↑ means increase.

Features Influenza A Virus SARS-CoV-2
graphic file with name vaccines-12-01220-i001.jpg graphic file with name vaccines-12-01220-i002.jpg
Year and pandemic name 1918 (H1N1), 1957 (H2N2), 1968 (H3N2), 2009 (H1N1), and Flu pandemics 2019 and COVID-19
Virus family Orthomyxoviridae Coronaviridae (genus β-CoVs)
Structure An enveloped, negative-sense, and single-stranded RNA virus; slightly ovoid or mostly round; diameter of 80–120 nm An enveloped, positive-sense, and single-stranded RNA virus; spherical or round in shape; diameter of 60–140 nm
Genome size 13.5 kb 29.9 kb
Mode of transmission Droplet, aerosol, direct contact, and fecal–oral route Droplet, aerosol, direct contact, and fecal–oral route
Replication sites Upper respiratory tract and, in severe cases, lower respiratory tract Starts from the upper respiratory tract, infects the lower respiratory tract, and spreads to other organs (cardiovascular, intestinal, kidney, and nervous system)
Incubation period 1–7 days 2–14 days (a maximum of 24 days)
Host receptor and entry Terminal glycosides of sialic acid ACE2 and TMPRSS2
Cellular tropism Epithelial cells of Respiratory tract: Alveolar Epithelial cells and ciliated cells Epithelial cells of the respiratory tract: alveolar epithelial cells, ciliated cells, basal cells of the olfactory epithelium, intestinal epithelial cells, renal parenchymal cells, and endothelial cells
Viral protein binding to host receptor HA Spike (S) protein
Replication Nuclear Cytoplasm
Symptom Fever, dry cough, sore throat, fatigue, and nasal congestion High fever, dry cough, fatigue, ARDS, and anosmia
Extrapulmonary complications In rare cases, myocarditis and encephalitis In most cases, anosmia, thrombosis, stroke, encephalitis, and diarrhea
Target for neutralizing antibodies HA and NA RBD of the spike protein
Hematological parameters Lymphopenia and CRP ↑ Type I interferon ↓, neutrophil counts ↑, and significant lymphopenia
Variants of concern (VOCs) 1957 H2N2, 1968 H3N2, and 2009 H1N1 Alpha, Beta, Gamma, Delta, and Omicron
Mortality rate 0.05–0.1% (seasonal influenza) ~1–3.4% (higher in early wave)
Vaccine availability Annual seasonal vaccines (inactivated, live) Multiple vaccines (mRNA, vector-based, inactivated)
Mutations/variants Antigenic shift and drift Frequent mutations with variants of concern (e.g., Delta and Omicron)
Treatment options Antivirals (e.g., oseltamivir and zanamivir) Antivirals (e.g., remdesivir, molnupiravir, and Paxlovid), mAbs
Complications Pneumonia and secondary bacterial infections Pneumonia, acute respiratory distress syndrome (ARDS), and multi-organ damage
References [26,27] [28,29]