Development of SARS-CoV-2 specific IgG and IgA antibodies in serum and milk with different SARS-COV-2 vaccines in lactating women

Abstract

Background Our main objective was to determine the evolution of IgG and IgA antibodies directed against SARS-CoV-2 protein S in the blood of lactating women and in breast milk. Methods A cohort of 110 uninfected and vaccinated breastfeeding women was followed-up for 6 months at the Marqués de Valdecilla University Hospital, Spain, in 2020. An additional group of 23 breastfeeding mothers who had no previously documented infection and had not been vaccinated against SARS-CoV-2 were included as a control group. The antibodies in blood and breast milk and their evolution at 6 months post-vaccination were analysed. Results One hundred ten breastfeeding mothers were included; 70 women (63.6%) were vaccinated with two doses of BNT162b2, 20 women (18.2%) received two doses of mRNA-1273, and 20 women (18.2%) received a single dose of ChAdOx1-S. No evidence of differences between concentrations of antibodies was found according to the type of vaccine, with the exception of serum IgA antibodies, which was higher in women vaccinated with mRNA-1273: mean [95%CI]: 0.05 AU/mL [0.03,0.06] with mRNA-1273, 0.02 AU/mL [0.01,0.03] with BNT162b2 and 0.01 AU/mL [0.00,0.03] with ChAdOx1-S, ANOVA p value = 0.03. The lack of difference between vaccines was also found when anti-S1 specific IgG in serum and breast milk were measured. Conclusions In lactating women vaccinated against COVID-19, anti-SARS-CoV-2 antibodies can be detected in both serum and breastmilk 6 months after receiving the second dose, although their concentrations decreased when compared with concentrations reached immediately after vaccination.

Anti-SARS-CoV-2 Immunoglobulins in Human Milk after Coronavirus Disease or Vaccination—Time Frame and Duration of Detection in Human Milk and Factors That Affect Their Titers: A Systematic Review

“…The Moderna vaccine also induces significantly higher titers of secretory antibodies compared with the rest of the vaccines [58]. Yet, six months post vaccination, no significant difference in antibody titers was observed among three types of vaccines [88].…”

“…No difference between detected antibody titers was described in women vaccinated with Moderna or Pfizer/BioNtech vaccines [32,52,57,63,68,88]. Only in one study of Gray KJ et al were higher IgA titers detected in the Moderna group after the 2nd dose [67].…”

Detection of IgA and IgG Antibodies against the Structural Proteins of SARS-CoV-2 in Breast Milk and Serum Samples Derived from Breastfeeding Mothers

“…In serum samples, the prevalence of anti-RBD (40%) and anti-N (60%) was higher than the other analyzed structural proteins of SARS-CoV-2. After vaccination, it has been reported that IgG is the predominant antibody, and its production continues six months after vaccination [34,35].…”

Breastfeeding during the COVID-19 pandemic

“…And because neonates have both innate and adaptive immune systems that are still developing, they have poor immunogenicity and are not likely to generate adequate immune response to the vaccine ( 77 , 96 ). Therefore, women who are planning to get pregnant can be encouraged to get vaccinated so that they can generate a sufficient repertoire of immunoglobulins to pass to the foetus when they get pregnant and confer passive immunity to neonate ( 96 , 50 ). But this should be done with the caution already discussed above; to avoid administration of the vaccine in the first trimester.…”