Influenza, or the flu, is a viral illness that, as reported by FamilyDoctor.org, affects the nose, throat and lungs. About 10 to 20 percent of Americans are infected with the flu annually. The flu vaccine has been touted as the most-effective way to prevent catching the flu, but side effects have been listed. The most confusing of these side effects are the ones that are similar to the symptoms of the flu. The vaccine does not actually cause influenza, but only causes symptoms, such as fever, shortness of breathing and chill, that mimic the disease.
Fever
The flu vaccine has been noted to cause a fever in some patients, according to Discovery Health. The fever is usually low grade and mild. This symptom usually only lasts 8 to 24 hours after the patient receives the flu shot. The fever is most probably a temporary reaction of the patient's immune system to the dead viral contents of the vaccine.
Sore Muscles
After receiving the flu vaccine, patients can exhibit various muscle aches and pains, as reported by the Centers for Disease Control and Prevention (CDC). These aches may be located at the sight of injection or be in other muscles throughout the body. The aches begin a short time after receiving the shot and last for one to two days.
Chills
Patients, especially children, may develop chills after they are injected with the flu vaccine, according to Discovery Health. The chills usually accompany the fever that develops after receiving the flu shot. The chills should only last for a couple of days after injection.
Swelling and Redness at Site of Injection
Patients can experience slight swelling and redness at the site of the injection, according to the Centers for Disease Control and Prevention (CDC). This is because of a local immune response to the vaccine. The area can also be painful to the touch. These symptoms near the site of infection usually only last a couple of days.
Difficulty Breathing
Patients may experience a difficulty breathing after being injected with the flu vaccine. The Centers for Disease Control and Prevention (CDC) report that this symptoms maybe a sign of a severe allergic reaction to the flu shot. If the patient experiences breathing problems along with wheezing, hives, paleness, a rapid heartbeat, dizziness, nausea or weakness, he should seek immediate medical attention. These symptoms of this allergic reaction occur within minutes to two hours after getting the shot, and usually in people who are allergic to eggs.
