“Meanwhile, flu typically causes a sudden onset of fever, severe tiredness and weakness, muscle and joint aches, a headache, ...

While both cold and flu share several symptoms, there are critical differences that can aid in identification. A cough is the most common crossover symptom; however, the nature and severity can vary.

"The key difference is that flu tends to come on suddenly and much more severely, whereas cold symptoms are milder and develop more gradually." ...