My grand-daughter has been sick since Tuesday. Monday she got a flu shot at school.Tuesday morning got up with a fever of 100 and complaining of a headache. Later that afternoon, developed a cough. Gave her Tylenol and did not send her to school. Tuesday she still had a fever so We went to the doctor. they did a strep test which turned out negative. He said it was a virus, to "let it run it's course". She is still running a fever tonight with a red throat, barking cough. Several kids in her class have been sick with this, but most of them are better. Should I worry about pneumonia? Bronchitis?