Breast Milk and COVID-19: From Conventional Data to “Omics” Technologies to Investigate Changes Occurring in SARS-CoV-2 Positive Mothers

Abstract

In this context of COVID-19 pandemic, great interest has been aroused by the potential maternal transmission of SARS-CoV-2 by transplacental route, during delivery, and, subsequently, through breastfeeding. Some open questions still remain, especially regarding the possibility of finding viable SARS-CoV-2 in breast milk (BM), although this is not considered a worrying route of transmission. However, in BM, it was pointed out the presence of antibodies against SARS-CoV-2 and other bioactive components that could protect the infant from infection. The aim of our narrative review is to report and discuss the available literature on the detection of anti-SARS-CoV-2 antibodies in BM of COVID-19 positive mothers, and we discussed the unique existing study investigating BM of SARS-CoV-2 positive mothers through metabolomics, and the evidence regarding microbiomics BM variation in COVID-19. Moreover, we tried to correlate metabolomics and microbiomics findings in BM of positive mothers with potential effects on breastfed infants metabolism and health. To our knowledge, this is the first review summarizing the current knowledge on SARS-CoV-2 effects on BM, resuming both “conventional data” (antibodies) and “omics technologies” (metabolomics and microbiomics).

Composition of Human Breast Milk Microbiota and Its Role in Children’s Health

“…It is well known that, for SARS-CoV-2, the detection of viral RNA in human milk is uncommon, and transmission along human milk has not been recorded [ 33 ]. Even if transmission of COVID-19 through breastfeeding appears unlikely, the infection could affect HMM, with breast milk being an expression of connection between mother and child [ 35 ]. During pregnancy, intestinal dysbiosis associated with COVID-19 inflammation could affect the composition of a newborn’s pioneer bacterial communities [ 8 ].…”

“…It was observed that greater the severity of the disease, greater was the intestinal dysbiosis. In affected patients, symbiotic bacteria were significantly reduced, with a corresponding enrichment of opportunistic flora [ 35 ]. Zuo et al [ 36 ] have shown that in the context of Firmicutes phylum, there was a reduction in some bacterial genera and an increase in other genera (i.e., Coprobacillus spp.)…”

“…Yeoh et al [ 37 ], in their research, revealed a reduction in bacteria belonging to the Actinobacteria and an increase in those belonging to the Bacteroidetes and Verrucomicrobia phyla [ 37 38 ]. Interestingly, dysbiosis continues even after recovery from SARS-CoV-2 infection [ 35 ]. Moreover, the reduction of Ruminococcus and Lachnospira spp.…”

“…(butyrate-producing bacteria) with a dramatic increase in Streptococcus spp. in COVID-19 affected patients is positively correlated with the levels of C-reactive protein and D-dimer [ 35 ]. Zhao et al [ 39 ] demonstrated a change in proteomics and metabolomics in human milk samples of COVID-19 positive mothers; three primary pathways were thought to be involved: complement activation, platelet degranulation, and macrophage function [ 40 ].…”

Neonates and COVID-19: state of the art

“… 67 – 74 sIgA against various SARS-CoV-2 epitopes [N-protein; S-protein linear epitopes (NTD, RBD-SD1) and S-protein conformational RBD epitopes] were found in convalescent donor milk, capable to neutralize viral activity and limit intestinal inflammation. 68 – 70 , 75 – 82 Lactoferrin prevents viral anchoring on host cell receptors and its concentration in breastmilk is negatively influenced by the severity of maternal COVID-19 infection during pregnancy. 83…”