Table 3 Correlation between concentrations of antibodies to protein α and Rib in sera from 29 cases with invasive group B streptococcal infection, 60 non‐infected controls, and 100 female blood donors.

	Correlation coefficient	95% CI
Anti‐α versus anti‐Rib in neonatal sera
Cases	0.82	0.65 to 0.91
Controls	0.73	0.58 to 0.83
Anti‐α versus anti‐Rib in maternal sera
Cases	0.88	0.78 to 0.95
Controls	0.80	0.69 to 0.88
Anti‐α versus anti‐Rib in sera from female blood donors	0.73	0.62 to 0.81

CI, Confidence interval.