Individuals receiving all shots will be monitored closely following each shot because of the small risk of anaphylaxis, a condition that can result in difficulty breathing and a sharp drop in blood pressure.
Each year about 200 adults and children in the United States die from food-related anaphylaxis, an extreme reaction that causes swelling of the throat and bronchial passages, shock, and a severe drop in blood pressure.
In a very few cases, milk allergy can cause anaphylaxis.
Anaphylaxis is thought to result from antigen-antibody interactions on the surface of mast cells, connective tissue cells that are believed to contain a number of regulatory, or mediator, chemicals.
Although children may lose their sensitivity to penicillin, if the reaction was urticarial or anaphylaxis, they are not re-challenged with the drug for safety reasons (i.e. it is not possible to predict who has lost sensitivity).