1. What are the early symptoms of pneumonia in babies? 1.1 Cough pneumonia is a respiratory infection, and one of the most common symptoms is cough. After babies contract pneumonia, they will have varying degrees of cough, ranging from dry cough to wet cough with phlegm. If your baby continues to cough, it is recommended to seek medical advice promptly. 1.2 Fever is also a cause of pneumonia in babies