Influenza (flu) is caused by one of several specific viruses. It usually occurs in the late fall, winter and early spring, but can occur any time. It is extremely contagious. One person coughing can expose everyone in that room to the flu. Symptoms start about a day or two after exposure. It comes on very quickly, one moment the person feels fine and the next they feel sick.
Symptoms commonly include fever, chills and body aches. Headache is common. Nasal congestion and a dry cough are usually present. The person will feel very tired and sick. Most of the time they do not have stomach symptoms such as nausea or diarrhea. A sore throat may occur.
There are a couple medications that can be used to lessen the symptoms, but they are only effective if started within 48 hours of the first symptoms. Medications can also be used to treat the cough. Antibiotics will not help.
Anyone who has influenza is also at risk of developing other bacterial infections during or immediately after having the flu. These include pneumonia, sinus infections, ear infections. If someone has a flu like illness and starts to have difficulty breathing or chest pain, they should be evaluated immediately.
The yearly flu shots help to protect against getting the flu. You need to get a new one each year in the fall. The experts in January or February each year decide which strains of influenza should be in the coming years flu vaccine. It is not an exact science, but most years they pick correctly and the flu vaccine prevents most people from getting the flu. The flu shot is a killed vaccine. You cannot get the flu from getting the flu shot.