Kinetics of delayed-type hypersensitivity to tuberculin induced by bacille Calmette-Guérin vaccination in northern Malawi.
Floyd, Sian;
Pönnighaus, Jorg M;
Bliss, Lyn;
Nkhosa, Prince;
Sichali, Lifted;
Msiska, Glyn;
Fine, Paul EM;
(2002)
Kinetics of delayed-type hypersensitivity to tuberculin induced by bacille Calmette-Guérin vaccination in northern Malawi.
The Journal of infectious diseases, 186 (6).
pp. 807-814.
ISSN 0022-1899
DOI: https://doi.org/10.1086/342416
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During 1986-1989, a bacille Calmette-Guérin (BCG) vaccine trial was carried out in northern Malawi. The effects of age, sex, and prevaccination delayed-type hypersensitivity (DTH) on the time course of the DTH response over 1-36 months after vaccination were studied in 2418 persons. DTH response increased rapidly, to peak at 31-90 days after vaccination, when most persons had a measurable response. This was followed by a marked decline by 181-365 days, particularly in those <15 years old at vaccination, followed by a more gradual decline. Prevaccination DTH was the single best predictor of postvaccination DTH. BCG-induced DTH responsiveness appears to decline more rapidly in tropical than in temperate environments. This may reflect high prevalence of exposure to other infections, which induce a Th2 bias or compete for "space" within the T lymphocyte compartment. The inability of some persons to mount a persistent DTH response probably reflects genetic background and/or environmental exposure history.