During the first few weeks of school, kids are back in close contact with other children, and exposed to new viruses and bacteria.
Viral infections can become colds, which usually last for three to five days.
And they usually go away on their own with fluids and rest.
Kids who were born premature, or who have breathing or heart conditions can have more severe complications, and may need extra care.
But for most, colds are necessary for building a strong immune system.
Dr. Giovanni Piedimonte of Cleveland Clinic Children said, "He's supposed to get this thing. It's part of life. It's part of the way the environment prepares us to be ready, you know, to be more resistant."
As time goes on, a child's immune system will get stronger, and they should get sick less often.
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