According to the Centers for Disease Control and Prevention, influenza affects 5 to 20 percent of the American population each year. The CDC also says that getting a flu shot each year is your best bet for avoiding the flu. The flu shot contains inactivated (killed) virus and is usually administered in the arm. In rare cases, people complain of mild influenza symptoms after getting the flu shot.
Symptoms in Adults
According to studies by CSL Biotherapies Inc., makers of the Afluria seasonal flu vaccine, approximately 10 percent of adults complained of headache, muscle ache, fatigue and malaise after receiving the vaccine. These symptoms were typically mild and resolved within one to two days. According to the CDC, a similar rate of symptoms was observed in patients who received saline instead of flu vaccine.
Symptoms in Children
In the same studies by CSL Biotherapies, approximately 10 percent of children also experienced symptoms of influenza after receiving the vaccine. Children reported a broader range of symptoms including irritability, rhinitis, fever, cough, loss of appetite, vomiting, diarrhea, headache, muscle aches and sore throat. These symptoms were usually mild and resolved within a few days.
Muscle Pain
The single most common symptom of influenza after immunization is muscle pain and tenderness, reported by more than 10 percent of adults and children. This is the same kind of muscle pain commonly associated with the influenza infection, however it is limited to the injection site rather than the generalized, whole-body pain characteristic of the infection. According to the CDC, muscle pain has only been reported in people who receive the flu shot. People who received intranasal vaccine (Flu Mist) do not seem to experience this symptom.
