Delayed-type hypersensitivity, mycobacterial vaccines and protective immunity

摘要: There is a longstanding debate over the implications of natural and vaccine-induced delayed type hypertensivity for protective immunity to mycobacterial infections. The identification correlates should help explain inconsistent behaviour BCG vaccines in different populations assist efforts devise improved vaccines. More than 70,000 subjects Karonga District, northern Malawi were skin tested with soluble antigens tubercle leprosy bacilli, then followed up five years tuberculosis incidence. Incidence rate ratios calculated compare levels prior test sensitivity, after controlling effects age, sex previous vaccination. vaccination protected against without persistent delayed-type hypersensitivity tuberculin or bacillus. In who had not received BCG, bacillus was associated strong protection leprosy. BCG-vaccinated unvaccinated subjects, there J-shaped relation between subsequent rates tuberculosis, lowest low grade sensitivity (induration 1-10 mm). This study shows that has leprosy: low-level (probably attributable environmental mycobacteria) protection, but vaccine-associated correlate vaccine-derived diseases.