Anaphylaxis following immunization is an extremely rare event. The US Adverse Event Reporting System data reveals 0.2 cases per million doses. Although anaphylaxis is a rare occurrence, this reaction can occur after a vaccination.
Anaphylaxis Vaccine Injury
FLU SHOT • MMR • DTAP/TDAP • OTHERS
The onset of an anaphylactic reaction is between 30 minutes and one day after immunization.
What is Anaphylaxis?
Anaphylaxis and anaphylactic shock is an acute, severe, and potentially lethal systemic allergic reaction that occurs as a single discrete event with simultaneous involvement of two or more organ systems. Most cases resolve without sequelae. Signs and symptoms begin minutes to a few hours after exposure to the allergen. Death, if it occurs, usually results from airway obstruction caused by laryngeal edema and bronchospasm and may be associated with cardiovascular collapse.
Possible Anaphylaxis Symptoms
Signs of Anaphylactic Shock
Cyanosis, hypotension, bradycardia, tachycardia, arrhythmia, edema of the pharynx and/or trachea and/or larynx with stridor and dyspnea. There are no specific pathological findings to confirm a diagnosis of anaphylaxis. Autopsy findings may include actute emphysema which results from lower respiratory tract obstruction, edema of the hypopharynx, epiglottis, larynx, or trachea and minimal findings of eosinophilia in the liver, spleen and lungs. When death occurs within minutes of exposure and without signs of respiratory distress, there may not be significant pathologic findings.