Detection of SARS-CoV-2 in Milk From COVID-19 Positive Mothers and Follow-Up of Their Infants

Abstract

Background: In the current SARS-Coronavirus-2 (SARS-CoV-2) pandemic little is known about SARS-CoV-2 in human milk. It is important to discover if breast milk is a vehicle of infection. Objective: Our aim was to look for the presence of SARS-CoV-2 RNA in the milk of a group of SARS-CoV-2 positive mothers from NorthWest Italy. Methods: This is a prospective collaborative observational study where samples of human milk from 14 breastfeeding mothers positive for SARS-CoV-2 were collected. A search of viral RNA in breast milk samples was performed by RT-PCR (Real-Time reverse-transcriptase-Polymerase-Chain-Reaction) methodology tested for human milk. All the newborns underwent a clinical follow up during the first month of life or until the finding of two sequential negative swabs. Results: In 13 cases the search for SARS-CoV-2 RNA in milk samples resulted negative and in one case it was positive. Thirteen of the 14 newborns were exclusively breastfed and closely monitored in the first month of life. Clinical outcome was uneventful. Four newborns tested positive for SARS-CoV-2 and were all detected in the first 48 h of life, after the onset of maternal symptoms. Also the clinical course of these 4 infants, including the one who received mother's milk positive for SARS-CoV-2, was uneventful, and all of them became SARS-CoV-2 negative within 6 weeks of life. Conclusion: Our study supports the view that SARS-CoV-2 positive mothers do not expose their newborns to an additional risk of infection by breastfeeding.

Preterm care during the COVID-19 pandemic: A comparative risk analysis of neonatal deaths averted by kangaroo mother care versus mortality due to SARS-CoV-2 infection

“…Breastfeeding transmission would require exposure to infectious breastmilk as well as acquisition via an oral or gastrointestinal route. SARS-CoV-2 RNA has been detected in breastmilk in rare cases [7/141 samples (5%) in 64 women] [15] , [16] , [17] , [18] . One case series reported a negative viral culture of a single RNA-positive milk sample, suggesting that SARS-CoV-2 does not represent replication-competent virus capable of infecting the baby [16] .…”

“…One case series reported a negative viral culture of a single RNA-positive milk sample, suggesting that SARS-CoV-2 does not represent replication-competent virus capable of infecting the baby [16] . Studies have reported two infected neonates who received SARS-CoV-2-positive breastmilk [ 17 , 18 ]. Both tested positive after the onset of maternal symptoms whilst rooming-in together; thus, horizontal transmission could not be excluded [ 17 , 18 ].…”

“…Studies have reported two infected neonates who received SARS-CoV-2-positive breastmilk [ 17 , 18 ]. Both tested positive after the onset of maternal symptoms whilst rooming-in together; thus, horizontal transmission could not be excluded [ 17 , 18 ]. Further, one neonate had two subsequent negative tests despite continuing to exclusively breastfeed whilst the mother was positive [17] , supporting the view that breastmilk is not a source of infection.…”

“…Both tested positive after the onset of maternal symptoms whilst rooming-in together; thus, horizontal transmission could not be excluded [ 17 , 18 ]. Further, one neonate had two subsequent negative tests despite continuing to exclusively breastfeed whilst the mother was positive [17] , supporting the view that breastmilk is not a source of infection. Breastmilk has immunological and antimicrobial components that protect against many invasive pathogens; however, its mitigatory effects against SARS-CoV-2 have yet to be determined.…”

“…Three newborns had elevated levels of SARS-CoV-2 IgM antibodies shortly after birth, but repeated nasopharyngeal swabs were negative [ 11 , 15 ]. While nucleic acid of SARS-CoV-2 has been detected in breastmilk, there is currently no evidence of viral transmission through breastfeeding [15] , [16] , [17] , [18] . Horizontal transmission may occur from infected family members or via nosocomial transmission in health facilities.…”