Algorithm for the management of patients with hypersensitivity reactions to vaccination
A detailed algorithm for diagnosing immediate hypersensitivity reactions in response to vaccination is presented, and revaccination approaches in patients with true allergic reactions are described.
Questions about possible allergic reactions that occur after vaccination are very often raised by patients and / or their parents and doctors. Immunization can be accompanied by the development of immediate and delayed types of immunologically mediated reactions. The estimated incidence of true allergic reactions or immediate hypersensitivity (GNT) to vaccination with conventional vaccines ranges from 1 per 50,000 doses with DTP vaccine to approximately 1 per 500,000-1,000,000 doses when using other vaccines.
In a large-scale study in New Zealand, data were collected on the use of 15 vaccines registered on the market over a period of 5 years. During the study, it was found that the administration of 450,000 doses of various vaccines causes an immediate hypersensitivity reaction.
Depending on the study design and the time after vaccination, the incidence of GST varies from 0.65 to 1.53 cases per 1,000,000 doses of vaccine administered. With some vaccines, especially in cases where allergens such as gelatin are components of the vaccine (for example, the Japanese encephalitis vaccine), a higher incidence of serious allergic post-immunization reactions may occur.
Despite the fact that true reactions of GNT with vaccines are rare, a large number of doses of various vaccines, in particular the most used, lead to the fact that this problem becomes very important from a clinical point of view.
The September issue of Pediatrics presents a detailed algorithm for diagnosing GNT reactions in response to vaccination and describes revaccination approaches in patients with true allergic reactions.
So, if you suspect that the reaction of GNT to vaccination is developing, a detailed medical history is required: the patient's age at the time of the reaction, specific symptoms, the temporary relationship of the onset of symptoms to the vaccine , another exposure to possible allergens, the prescribed treatment and its effectiveness, the duration of symptoms, the time necessary to complete the cessation of symptoms of GNT and information on previous vaccinations.
It should also be noted that the patient has a history of atopic diseases, including food or drug allergies, atopic dermatitis, bronchial asthma and allergic rhinitis. Based on all of the above information, the doctor will need to conclude whether the symptoms that have appeared in the patient are really a reaction to the vaccine and, if so, is this reaction mediated by IgE.
In allergological tests, a whole vaccine is generally used, although specific components have been developed for certain vaccines to be tested. Preferably, skin tests are performed by a specialist (allergist) using a specific vaccine from the same manufacturer, which would have caused a reaction to the previous administration. The allergy testing algorithm includes 4 main steps: