The coronavirus disease 2019 and influenza 2009 pandemics compared

Coronavirus disease 2019 pandemicInfluenza 2009 pandemic
Causative virusSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2)Influenza A (H1N1)
Mode of transmissionRespiratory droplets most common, but contact with surfaces contaminated with viral particles and airborne routes are possible
Number of secondary transmissions from 1 infected person2.51.7
Incubation period (days)2–142
Interval from symptom onset to maximum infectivity (days)02
Duration of infectivity after onset of illness (days)8–105–7
Typical course of illnessGradual 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 illnessSudden onset of acute illness, which lasts 2–5 days, followed by milder symptoms that can last for several weeks
Typical clinical presentationFever, headache, myalgia, malaise, and dry cough; less commonly, vomiting and diarrhea
Unique manifestationsSudden loss of smell or tasteNone
Asymptomatic or presymptomatic30%–40%20%
Illness requiring hospitalization20%5%–10%
Illness requiring intensive care1/16,0001/104,000
ComplicationsRespiratory failure, myocarditis, encephalitis, myositis, multi-organ failure, and secondary bacterial pneumonia
Case fatality rate0.5%–1%0.02%–0.05%
Antiviral therapyIntravenous remdesivir (investigational)Oral oseltamivir, inhaled zanamivir, intravenous peramivir, and oral baloxavir
Dexamethasone therapyOnly if hypoxicNot recommended
Convalescent plasma therapyInvestigational, only for severe cases
Preventive measures other than vaccineSocial distancing, hand hygiene, face masks, isolation and contact tracing of confirmed cases, and quarantine of those exposed
Preventive vaccineIn development; now 6 months into the pandemicWas developed and approved within 5 months
Pandemic durationOngoing; 8 months so far15 months