Can multiple doses of BCG vaccine protect against asthma?

Objective: To compare BCG vaccination involving a single intradermal dose and that involving multiple doses, one given with the multiple puncture technique, in terms of the protective effect against the subsequent onset of asthma.

Methods: A retrospective cohort study involving 2,311 individuals having received the BCG vaccine. The patients were classified according to the number of doses of BCG vaccine administered (one; two; or three or more).