Pneumonia is more common in children younger than 5, and it can range from mild (like mycoplasma pneumonia, also known as "the walking pneumonia") to serious and potentially life-threatening.

While respiratory syncytial virus (RSV) may present like the common cold in many healthy children, it can be dangerous in babies and some young children.

All children 6 months and up should get the flu vaccine yearly. While some side effects may occur, they are usually mild and infrequent. Learn more here.

The flu is a highly contagious infection that can cause a sudden high fever at or above 100.4°F (38°C), body aches, cough, and more.

The common cold is one of the most common illnesses among children—in fact, most children will have 8 to 10 colds by the time they’re two years old.

While a fever in older babies are signs that the immune system is working properly, a fever in a newborn or infant less than 3 months old is considered a medical emergency requiring immediate medical attention.