Multiple comparison of dried BCG vaccines: stability at 37 degrees C and persistence of strains in the mouse spleen.

The Gabriel test was used for multiple comparison of the stability of vaccines stored at 37 degrees C over a 28 day period and of the long-term relative persistence capacity (RPC) in mice spleen (residual virulence) over a 547 day period following intravenous vaccination with 12 BCG dried products. Multiple comparisons were performed after rejected null hypotheses (Anova, Regranal), with ranked mean viable units 10(6) ml-1 estimates (VU) of vaccines and with ranked mean RPC values in spleen determined with five sampling and on nine autopsy days, respectively. Results showed that VU X 10(6) ml-1 values of the compared vaccines at day 0 varied between 1.1 and 27.0 X 10(6) ml-1 and formed two homogeneous subsets. The heat stability test showed that the VU X 10(6) ml-1 values of the vaccines decreased parallely but at day 28 only six vaccines showed a survival rate over 20%. The RPC model showed that the trends of early multiplication and of late persistence capacity depended on the i.v. BCG VU doses. The Regranal of late RPC indicated that the decrease of BCG VU in mice spleen from 84 to 547 days was parallel and that six strains persisted over 20% at day 360. The overall RPC on the nine autopsy days of the BCG strains was evaluated with Kendall concordance test. In contrast with pairwise comparison, the Gabriel test reduces the risk of type I error in statistical inference at the 5% experimental level and selects the homogeneous subsets of ranked parameter estimates of the compared products.(ABSTRACT TRUNCATED AT 250 WORDS)