In a typical year, the U.S. Centers for Disease Control and Prevention recommends influenza vaccination for virtually everyone over the age of 6 months. In the 2010-2011 flu season, flu shots, which contain inactivated or killed forms of the virus, are one option for protection against a strain of influenza B, the H1N1 virus that was prevalent in 2009 and an H3N2 virus. The vaccine may vary from year to year as major strains of the influenza-causing viruses mutate. There is a potential for an allergic reaction to any form of the vaccine.
Causes
Influenza viruses for vaccines are grown in eggs, which is problematic for individuals with known allergies to the protein in eggs. Other individuals are allergic to various components of the vaccine, including the preservatives used to stabilize the solution, according to the CDC.
Symptoms
An allergic reaction to a flu shot typically starts with a cough and hoarseness, but may soon escalate to a state called anaphylaxis. Marked by facial swelling, difficulty breathing, hives, weakness, fatigue, abdominal pain, rapid heartbeat and dizziness, anaphylaxis is a true medical emergency. Seek immediate medical attention for any of these symptoms.
Time Frame
While life-threatening allergic reactions to the flu vaccine are rare, they usually start within a few minutes to a few hours after the injection, the CDC reports.
Misconceptions
Some people develop uncomfortable or worrisome symptoms following the flu shot and mistakenly believe they are having an allergic reaction. It's not uncommon to have mild redness, itching, swelling, or soreness at the injection site for a day or two. This response is a simple injection reaction and not an allergic response, says Flu.gov. Individuals who are anxious about needles and faint after receiving the shot, but quickly recover, are also not allergic to the vaccine.
Expert Insight
According to the CDC, flu shots are not recommended for individuals with a severe allergy to chicken eggs or people who have had a severe reaction to an influenza vaccine in the past. Family members and other close contacts can help provide immunity for allergy-prone children and adults by getting themselves vaccinated as early as possible.
Tip
People who have been injured by a severe reaction to influenza vaccine can apply for compensation through the National Vaccine Injury Compensation Program.
