Generally speaking, if a baby has a cold caused by a common viral infection and receives symptomatic treatment, the symptoms can usually be controlled within three to five days. If it is a severe cold or influenza, the symptoms can be more severe and may include repeated fever, runny nose, and sneezing, lasting longer, about seven days, or even up to ten days. If there is a bacterial infection following the cold, the duration may be even longer and would require specific analysis based on the actual situation.