In view of the data scarcity to guide decision-making, we evaluated how BNT162b2 and mRNA-1273 vaccines impact the immune response of lactating women and the protective profile of breastmilk. Compared to controls, lactating women had higher frequency of circulating RBD-memory B cells and higher anti-RBD antibody titers, but similar neutralizing capacity. We show that upon vaccination, immune transfer to breastmilk occurs through a combination of anti-spike secretory IgA (SIgA) antibodies and spike-reactive T cells. While we found that the concentration of anti-spike IgA in breastmilk might not be sufficient to directly neutralize SARS-CoV-2, our data suggest that cumulative transfer of IgA might provide the infant with effective neutralization capacity. Our findings put forward that breastmilk might convey both immediate, through anti-spike SIgA, as well as long-lived, via spike-reactive T cells, immune protection to the infant. Further studies are needed to address this possibility and to determine spike-T cells functional profile.
Background Immunological protection via breastfeeding is well known. The immunological profile of human milk changes during lactation. No clinical trials have been conducted in lactating women with the newest mRNA vaccines against SARS- CoV-2. A Few studies have shown the presence of antibodies in breastmilk after vaccination. The aim of this work is to study possible antibodies transfer via breastmilk and also the immunological characteristics of lactating women compared to non-lactating women, after using the BNT162b2 Pfizer vaccine. Methods This is a prospective cohort study with a convenience homogenous sample of 24 healthcare workers (14 lactating and 10 non-lactating women) enrolled at the time of COVID-19 vaccination. Clinical data was registered in a questionnaire. Titers of SARS-CoV-2 spike IgG, IgA and IgM were quantified in post vaccination blood and human milk. Antibody quantification was performed by an in-house ELISA to SARS-CoV-2 trimeric spike protein. Results All women showed immunity after vaccination with positive antibodies for IgM, IgA and IgG antibodies. The dominant serum antibody response was IgG. Modest levels of antibodies in breastmilk of lactating mothers were observed in this study, especially IgG in 42.9%. There was a moderate association between higher titers of IgG and a longer duration of breastfeeding (R= 0.55, p=0.041). Conclusions Evidence of antibody transfer in human milk after COVID-19 vaccination is scarce. The presence of antibodies in human milk is reported, but immunization through breastfeeding is still to be established.
In view of data scarcity to guide decision-making in breastfeeding women, we evaluated how mRNA vaccines impact immune response of lactating health care workers (HCW) and the effector profile of breast milk transferred immune protection. We show that upon BNT162b2 vaccination, immune transfer via milk to suckling infants occurs through secretory IgA (SIgA) and T cells. Functionally, spike-SIgA was non-neutralizing and its titers were unaffected by vaccine boosting, indicating that spike-SIgA is produced in a T-cell independent manner by mammary gland. Even though their milk was devoid of neutralizing antibodies, we found that lactating women had higher frequencies of RBD-reactive circulating memory B cells and more RBD-IgG antibodies, when compared to controls. Nonetheless, blood neutralization titers in lactating and non-lactating HCW were similar. Further studies are required to determine transferred antibodies and spike-T cells complete functional profile and whether they can mediate protection in the suckling infant.HighlightsMilk and blood responses to BNT162b2 vaccine are initially isotype discordantImmune transfer via milk to suckling infants occurs by spike-reactive SIgA and T cellsSpike-reactive SIgA in the breastmilk is non-neutralizing and T-cell independentLactating vs non-lactating HCW had distinct cellular responses, despite similar NT50
Virtual poster abstractsof pelvic abscess must be explored in these patients. Our study revealed a sigmoid colon perforation due to carcinoma invasion which resulted in bilateral TOA. The multidisciplinary approach was essential for correct diagnosis and proper management of this malignancy. VP03.06Tailgut cyst: a curious incidental finding on gynecological ultrasound
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