TABLE 2.

Evaluation of the DIVA potential of the Enferplex TB assaya

Test performed% of animals testing positive (95% CIb)No. of animals testing positive/total no.Pc
Enferplex TBd0 (0, 9)0/39NA
SICCT
    Standard interpretation66.6 (49.8, 80.9)26/39<0.0001
    Severe interpretation87.2 (72.5, 95.7)34/39<0.0001
Bovigam IGRAe
    PPD-B and -A38.5 (23.4, 55.4)15/39<0.0001
    ESAT-6 and CFP-107.7 (1.6, 20.8)3/390.2403
  • a Calves were neonatally vaccinated with BCG, and serum samples were collected 6 months postvaccination and 2 to 5 weeks after the SICCT was performed.

  • b CI, confidence interval.

  • c For comparison of the SICCT or the Bovigam IGRA to the Enferplex TB assay by Fisher's exact test. To account for multiple-comparison errors, a P value smaller than 0.0125 was used to define statistical significance. NA, not applicable.

  • d Animals tested negative with all 5 of the interpretation criteria.

  • e For the Bovigam IGRA, the cutoff was a difference of >0.1 OD450 unit between the PPD-B and PPD-A results or between the results with the cocktail of ESAT-6- and CFP-10-derived synthetic peptides and the results with the no-antigen control.