Incubation after exposure is 24 to 48 hours. Influenza can affect both sexes, all ages, but it is unusual in infants.
Muscle aches, including backache.
Cough, usually with little or no sputum. The viruses are spread by personal contact. Your child should avoid risks listed above. A child with chronic heart or lung disease should have a yearly influenza vaccine injection. Medical history and physical exam by a doctor.