Influenza is an illness capable of affecting the entire respiratory tract from the nose and throat down to the bronchial tubes and lungs. It is caused by a group of 3 viruses (influenza A, B or C). Unfortunately these viruses keep changing from year to year, forming new outer coats which our immune system cant recognize. This means that even if you or your child had influenza in the past, this years virus may be different enough to infect either of you again.
