The coronavirus disease 2019 and influenza 2009 pandemics compared
| Coronavirus disease 2019 pandemic | Influenza 2009 pandemic | |
|---|---|---|
| Causative virus | Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) | Influenza A (H1N1) |
| Mode of transmission | Respiratory droplets most common, but contact with surfaces contaminated with viral particles and airborne routes are possible | |
| Prevalence | 0.11% | 25% |
| Number of secondary transmissions from 1 infected person | 2.5 | 1.7 |
| Incubation period (days) | 2–14 | 2 |
| Interval from symptom onset to maximum infectivity (days) | 0 | 2 |
| Duration of infectivity after onset of illness (days) | 8–10 | 5–7 |
| Typical course of illness | Gradual onset, then sudden escalation in severity, then recovery within 2 weeks in those with mild or moderate illness, and 3–6 weeks in those with severe illness | Sudden onset of acute illness, which lasts 2–5 days, followed by milder symptoms that can last for several weeks |
| Typical clinical presentation | Fever, headache, myalgia, malaise, and dry cough; less commonly, vomiting and diarrhea | |
| Unique manifestations | Sudden loss of smell or taste | None |
| Asymptomatic or presymptomatic | 30%–40% | 20% |
| Illness requiring hospitalization | 20% | 5%–10% |
| Illness requiring intensive care | 1/16,000 | 1/104,000 |
| Complications | Respiratory failure, myocarditis, encephalitis, myositis, multi-organ failure, and secondary bacterial pneumonia | |
| Case fatality rate | 0.5%–1% | 0.02%–0.05% |
| Antiviral therapy | Intravenous remdesivir (investigational) | Oral oseltamivir, inhaled zanamivir, intravenous peramivir, and oral baloxavir |
| Dexamethasone therapy | Only if hypoxic | Not recommended |
| Convalescent plasma therapy | Investigational, only for severe cases | |
| Preventive measures other than vaccine | Social distancing, hand hygiene, face masks, isolation and contact tracing of confirmed cases, and quarantine of those exposed | |
| Preventive vaccine | In development; now 6 months into the pandemic | Was developed and approved within 5 months |
| Pandemic duration | Ongoing; 8 months so far | 15 months |