Prediction of residual immunity to smallpox, by means of an intradermal skin test with inactivated vaccinia virus.
BACKGROUND
Intradermal skin testing with inactivated vaccinia virus was evaluated for its prediction of residual immunity to smallpox.


METHODS
An intradermal skin test was performed with heat-inactivated Lancy-Vaxina. Two days later, the subjects were vaccinated with Lancy-Vaxina. The skin lesions resulting from this vaccination were used as a surrogate marker of residual immunity to smallpox, and this surrogate marker was compared with the available indicators of susceptibility to smallpox.


RESULTS
Of the 83 subjects, 30 (36%) showed the typical primary response after vaccination (i.e., absence of residual immunity), whereas 34 (41%) showed the typical revaccinee's response (i.e., presence of residual immunity); the remaining 19 (23%) had an indeterminate response and were excluded from the final analysis. The sensitivity and specificity of the intradermal skin test (induration size, >or=4 mm) for prediction of residual immunity to smallpox were 85% and 97%, respectively, whereas those of a positive vaccinia-specific interferon- gamma -producing T cell response (>or=9 spot forming cells/10(6) peripheral-blood mononuclear cells) were 32% and 63%, respectively, and those of a positive neutralizing antibody (titer, >or=1 : 8) were 79% and 80%, respectively.


CONCLUSIONS
The intradermal skin test appears to be a simple and reliable method for prediction of residual immunity to smallpox.
Kim
Sung-Han
SH
Department of Virology, National Institute of Health, Seoul, South Korea.
Bang
Ji-Whan
JW
Park
Kyung-Hwa
KH
Park
Wan-Bum
WB
Kim
Hong-Bin
HB
Kim
Nam-Joong
NJ
Jee
Youngmee
Y
Cho
Haewol
H
Oh
Myoung-don
MD
Choe
Kang-Won
KW
D000328:Adult; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D007428:Intradermal Tests / Q000379:methods*; D008297:Male; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D012899:Smallpox / Q000276:immunology*; D012900:Smallpox Vaccine / Q000276:immunology*; D014616:Vaccinia virus / Q000276:immunology*; D038301:Virus Inactivation
D012900:Smallpox Vaccine; D007371:Interferon-gamma