Groups of BCG-vaccinated guinea pigs were given a single Mantoux skin test 4 to 69 weeks after vaccination. The skin reactions tended to develop more slowly the longer the interval since BCG vaccination. Relatively quickly developing tuberculin skin reactions may be characteristic not only for repeated testing, but also for skin tests taken shortly after BCG vaccination.
In persons with waning sensitivity to mycobacterial antigens, skin reactivity to tuberculin may be maintained or enhanced as a result of tuberculin testing. Similar phenomena have been observed in guinea-pigs. As tuberculin testing may lead to antibody formation, the "booster" effect might be due to circulating antibody. However, a series of nine pilot experiments including blood and serum transfer from boosted to unboosted BCG-vaccinated guinea-pigs gave no support to this hypothesis.
