Pertussis vaccination during pregnancy or immediately after delivery is a strategy that is increasingly being recommended to protect young infants from disease. Breast milk contains disease-specific antibodies that can contribute to the protection of young infants. The composition of breast milk could be altered by vaccination during pregnancy or near delivery. However, the quantification of these antibodies in breast milk lacks standardization.
In this paper, sample preparation procedures and detection methods for total and antipertussis toxin (anti-PT) secretory immunoglobulin (sIg) A are proposed that can be accurately repeated and are in accordance with European Medicines Agency and Food and Drug Administration requirements. Both antibody analytes were measured in breast milk samples of lactating women obtained 8–9 weeks postpartum to compare different maternal pertussis vaccination strategies: vaccination during pregnancy, shortly after or at delivery (cocoon), less than 5 years before delivery or more than 5 years before delivery.
The validated immunoassays could quantitatively detect total and anti-PT sIgA in the processed breast milk samples. Significantly higher levels of anti-PT sIgA were measured in breast milk after pertussis vaccination during pregnancy or at delivery [geometric mean concentration (GMC): 2.56 and 2.15 IU/mg] in contrast to mothers with no recent (>5 years) pertussis vaccination (GMC: 0.96 IU/mg; P = 0.014 and P = 0.028).
Vaccination against pertussis in the second/third trimester of pregnancy or immediately postpartum significantly increased the levels of anti-PT sIgA in breast milk.
From the *Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, and †Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
Accepted for publication February 18, 2015.
The authors have no conflict of interests relevant to this article to disclose. The work is supported by Research Foundation Flanders (G.A032.12N). A research grant from the University of Antwerp (BOF KP 28039) was obtained for laboratory analyses. S.D.S. is a research assistant from the University of Antwerp. E.L. owns a postdoctoral mandate supported by Research Foundation Flanders (FWO 12D6114N).
Address for correspondence: Elke Leuridan, MD, PhD, VAXINFECTIO, University of Antwerp, Campus Drie Eiken (D.R.213), Universiteitsplein 1, 2260 Wilrijk, Belgium. E-mail: firstname.lastname@example.org