Table 5 Associations, adjusted for gestational age and sex, between invasive group B streptococcal (GBS) infection and concentrations of antibodies to protein α and Rib in serum from neonates.

Infecting isolate	No of sera (cases and controls)	Antibody concentration
		Anti‐α			Anti‐Rib
		OR	95% CI	p Value	OR	95% CI	p Value
All isolates*	89	0.11	0.003 to 3.86	0.22	0.07	0.004 to 1.38	0.08
α‐expressing	73	1.17	0.02 to 67.22	0.94	0.43	0.02 to 12.00	0.62
Rib‐expressing	74	0.0007	0.000 to 0.54	0.03	0.002	0.000 to 0.57	0.03

Analyses were by multiple logistic regression including all neonates with GBS infection and controls (n  =  89), neonates with GBS infection caused by strains expressing protein α and Rib, and controls (n_α  =  73 and n_Rib  =  74).

*All GBS isolates with protein α, Rib, or neither of these proteins expressed on the bacterial surface.

OR, Odds ratio; CI, confidence interval.