Breast Milk Antibody Levels in Tdap-Vaccinated Women After Preterm Delivery

Abstract

Introduction/Background & Aims Enrichment of breast milk (BM) with immunoglobin (Ig)A and IgG, through maternal vaccination, could help young infants combat targeted pathogens. However, evidence on this effect after preterm delivery is lacking. This study investigated the total and anti-pertussis toxin (anti-PT) specific IgA and IgG production in BM after term or preterm delivery in the presence of maternal Tdap (tetanus, diphtheria, acellular pertussis) vaccination. Methods Serum and BM samples of lactating women, who delivered at term or prematurely and did or did not receive Tdap vaccine (Boostrix®, GSK Biologicals) during pregnancy, were collected as part of a clinical study (N=234, NCT02511327). Anti-PT IgA/IgG (IBL®; MSD®) and Total IgA/IgG (Thermofisher®, on BM samples only) immunosorbent assays were performed on all samples collected at 72 hours, 4, 8, and 12 weeks postpartum. Results BM after preterm delivery contained anti-PT IgA and IgG geometric mean concentrations (GMCs) comparable to those after term delivery (e.g. colostrum anti-PT IgA: 5.39 International Units per milliliter (IU/mL) vs 6.69 IU/mL, respectively). Maternal Tdap vaccination induced significantly higher anti-PT IgG GMC’s in colostrum of vaccinated compared to unvaccinated women delivering at term (0.110 IU/mL vs 0.027 IU/mL, p=0.009). Compliance with postpartum vaccination led to no differences in BM after 4 weeks postpartum. Anti-PT antibodies persisted up to 12 weeks postpartum. Conclusions This study provides evidence that maternal Tdap vaccination induces high Ig levels in BM after both term and preterm delivery and that these antibodies remain abundantly present throughout lactation, possibly offering additional mucosal protection during the most vulnerable period in early life.

SARS-CoV-2 Antibodies Detected in Mother’s Milk Post-Vaccination

“…In contrast to the IgA-dominant antibody response in the milk of women previously infected with SARS-CoV-2 ( Fox et al, 2020 ), our results indicate that the post-vaccine antibody response in human milk is IgG dominant. This is consistent with previously published studies about SARS-CoV-2 vaccination ( Gray et al, 2021 ; Perl et al, 2021 ) and has also been observed after Tdap vaccination in pregnancy ( Orije et al, 2021 ). One potential explanation for this difference is that vaccinated mothers are exposed to viral antigen via intramuscular injection, whereas infected mothers have immunological education occurring in the mucosa, where IgA plays a greater role.…”

The protective role of maternal genetic immunization on maternal‐fetal health and welfare

“…85,102,112,113 It has been documented that inactivated influenza virus vaccine, 23-valent pneumococcal polysaccharide vaccine, and meningococcal vaccine, induced five times stronger specific antibody levels in milk until the 2nd month postpartum, and high specific IgM levels in milk up to 6 months postpartum compared with a non-vaccinated group. 114,115 Moreover, vaccinationinactivated SARS-CoV-2 and influenza vaccines during pregnancy and lactation increased specific levels of IgA in milk. 116,117 Another study revealed that maternal immunization against Streptococcus pneumoniae increased the IgG levels in human milk and protected the infant against infection.…”

“…Studies have shown that the administration of vaccines during pregnancy might produce specific IgG in breast milk for periods ranging from 12 weeks to 1 year postpartum 85,102,112,113 . It has been documented that inactivated influenza virus vaccine, 23‐valent pneumococcal polysaccharide vaccine, and meningococcal vaccine, induced five times stronger specific antibody levels in milk until the 2nd month postpartum, and high specific IgM levels in milk up to 6 months postpartum compared with a non‐vaccinated group 114,115 . Moreover, vaccination‐inactivated SARS‐CoV‐2 and influenza vaccines during pregnancy and lactation increased specific levels of IgA in milk 116,117 .…”

Effects of Vaccination Against Influenza, Pertussis, and COVID-19 on Human Milk Antibodies: Current Evidence and Implications for Health Equity

“…Further, infants with pertussis whose mothers received the TdaP vaccine had lower risks of hospitalization, ICU admission, and shorter hospital stays compared to mothers who were not vaccinated ( 71 ). In summary, vaccination with Tdap during or shortly after pregnancy greatly increases the level of anti-PT antibodies in human milk ( 64 – 66 , 72 , 73 ) and may contribute to the protection provided to the infant against pertussis infection.…”