Dermal testing of vaccines for children at high risk of allergies.

Vaccinations for children with allergic diseases often need to be postponed or terminated because of the presumed risk of an immediate-type allergic reaction such as anaphylaxis. A new skin test protocol for predicting allergic reactions using the vaccine itself and the following stepwise vaccination method were developed and tested. Intradermal tests using 1:10 and 1:100 diluted measles vaccine indicated that the former was superior to the latter because a positive reaction against 1:10 diluted vaccine was found in 28.6% of 49 patients with severe allergic diseases including bronchial asthma, atopic dermatitis, food allergies and allergies to two or more allergens with high levels of IgE, as compared with the reaction against 1:100 diluted vaccine in 10.2% of the patients. Patients negative for 1:10 skin tests were safe from the following full-dose vaccine shots. Three patients showed very strong local reactions against measles vaccine, and avoided receiving the following full-dose shot. Positive reactions to skin tests of 1:10 diluted vaccine were found in 11 patients, who were given stepwise vaccinations. Three patients had adverse reactions, and two of them had been negative for 1:100 skin tests. In the case of influenza vaccine, skin tests were again more sensitive to 1:10 than to 1:100 diluted vaccine, because 3 out of 14 patients with positive reactions showed immediate-type adverse reactions against the following stepwise vaccinations, and 1 of them was negative for the 1:100 skin test. Moreover, the results of the skin prick test (undiluted vaccine) and the intradermal skin test (1:10 diluted vaccine) indicated that the latter was more useful in both cases of measles (54 patients) and influenza vaccine (69 patients). Overall, the skin test using 1:10 diluted vaccine was the more suitable for predicting an immediate-type reaction to measles and influenza vaccinations. Patients having negative 1:10 skin tests can be expected to show no adverse reactions to the remaining injections and even the positive subjects will complete the course of vaccine doses by the stepwise method.