Further studies on effect of storage at high temperatures upon allergenic potency of dried BCG vaccine.

The authors describe experiments which were carried out to determine the effect on the allergenic potency of dried glutamate BCG vaccine and dried sucrose BCG vaccine of storage at high temperatures.The two vaccines in question were inoculated into school-children after storage for one month at the following temperatures: 5 degrees C, 30 degrees C, 38.5 degrees C and 50 degrees C. The tuberculin reactions of these children were examined 4 and 12 months after the vaccination, both Japanese Old Tuberculin (OT) and Danish purified tuberculin (PPD) being used in the testing.After storage for one month at temperatures exceeding 30 degrees C, the allergenic potency of the dried glutamate vaccine was consistently higher than that of the dried sucrose vaccine. The decrease in potency of the dried sucrose vaccine was evident after storage at 30 degrees C for one month, whereas the dried glutamate vaccine showed a significant decrease in potency only after storage at 50 degrees C for the same period. This tendency was observed in the tuberculin testing up to 12 months after vaccination, and, furthermore, was apparent whether the post-vaccination tuberculin allergy was estimated in terms of erythema with OT or in terms of induration with PPD.