COVID-19 compared to other epidemic coronavirus diseases and the flu

Table 2 Comparison of coronavirus disease 2019 and the flu

Factors	COVID-19	Flu
Incubation period	2-14 d	1-4 d
Symptoms[3]	The most common symptoms are cough, sore throat, headache, body weakness and myalgia (fatigue) due to severe respiratory illnesses associated with shortness of breath and breathing difficulties. In severe cases, individuals may show symptoms of pneumonia	Typical flu symptom is characterized by a sudden onset of fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and a runny nose
Case fatality rate[8,20]	Initial reports from China suggest the case fatality rate is at least 2.2% (unresolved), and United States 3.9% as of April 12, 2020	The case fatality rate for the flu in the United States is < 0.1%
Virus transmission[17,21]	The basic reproduction number, R0 is about 3.2	The production number of the flu is about 1.28
Characteristic	Pandemic	Endemic, potential for epidemic or pandemic
Prevention[19,22]	There is no approved vaccine for COVID-19	There is an annual flu vaccine

COVID-19: Coronavirus disease 2019; R₀: the average number of people who catch the virus from a single infected person.