The most common symptoms of a cold are a cough, runny nose, a stuffy nose, and a sore throat. Other issues are sore muscles, feeling tired, headache, and not wanting to eat. Around 40% of people with colds have a sore throat, while around 50% have a cough. Muscle ache happens in about half of the cases. A fever is an uncommon symptom in adults, but it is common in infants and young children. The cough caused by a cold is usually mild compared to a cough caused by influenza (the flu). A cough and a fever indicate a higher likelihood of the flu in adults. A number of the viruses that cause the common cold may also result in no symptoms. The color of the mucus that is coughed up from the lungs (sputum) may vary in color from clear to yellow to green. This color does not indicate if an infection is caused by viruses or bacteria.