[Consensus position document on the child with an allergic reaction after vaccination or an allergy to vaccine components].

Vaccinations are one of the main public health tools for the control of vaccine-preventable diseases. If a child is labeled to have had an allergic reaction to a vaccine, the next immunizations will probably be suspended in that child, with the risks involved in this decision. The rate of severe allergic reactions is very low, ranging between 0.5-1/100,000 doses. The causes of allergic reactions to vaccines, more than the vaccine itself, are often due to residual protein components in the manufacturing process, such as gelatin or egg, and rarely to yeast or latex. Most of vaccine reactions are mild, localized at the site of injection, but in some circumstances, severe anaphylactic reactions can occur. If an immediate-type allergic reaction is suspected when vaccinating, or a child allergic to some of the vaccine components has to be vaccinated, a correct diagnosis of the possible allergy has to be made. The usual components of each vaccine should be known, in order to determine if vaccination can be performed safely on the child.