Undermining breastfeeding will not alleviate the COVID-19 pandemic – Authors' reply
Authors: Rüdiger Groß, Carina Conzelmann, Janis A Müller, Frank Reister, Frank Kirchhoff, Jan Münch
Journal: The Lancet (2020)

In the ongoing COVID-19 pandemic, questions regarding possible methods of virus transmission, including the safety of breastfeeding by mothers who are infected, are of great importance. We reported1Groß R Conzelmann C Müller JA et al.Detection of SARS-CoV-2 in human breastmilk.Lancet. 2020; 395: 1757-1758Summary Full Text Full Text PDF PubMed Scopus (290) Google Scholar the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA (not viral particles, as incorrectly stated by Natalie Shenker and colleagues) in consecutive milk samples from an infected mother and interpreted our findings with the greatest caution. In particular, we did not claim that SARS-CoV-2 is transmitted via contaminated breastmilk or that breastfeeding should be discontinued by mothers with the infection. Instead, we emphasised that more research is required. At the time of writing, there are eight other reports of SARS-CoV-2 RNA detection in milk samples,2John Hopkins Bloomberg School of Public HealthCOVID-19, breastfeeding, infant feeding, breast milk – literature repository.http://hopkinshumanitarianhealth.org/assets/documents/COVID-19_Breastfeeding_Infant_Feeding_Breast_Milk_-_Literature_Repository_(Feb-Aug_2020)_(updated_21_August)_FINAL.pdfDate: Aug 21, 2020Date accessed: August 24, 2020Google Scholar in several cases at multiple timepoints during the course of the infection. Consequently, the now-published review articles that we cited in our Correspondence,2John Hopkins Bloomberg School of Public HealthCOVID-19, breastfeeding, infant feeding, breast milk – literature repository.http://hopkinshumanitarianhealth.org/assets/documents/COVID-19_Breastfeeding_Infant_Feeding_Breast_Milk_-_Literature_Repository_(Feb-Aug_2020)_(updated_21_August)_FINAL.pdfDate: Aug 21, 2020Date accessed: August 24, 2020Google Scholar which summarised the peer-reviewed publications at the time of submission, are already outdated. In most of these studies, care was taken to avoid environmental contamination (eg, by breast disinfection or washing if feeding occurred before sampling), as also indicated in our Correspondence. Shenker and colleagues suggest that the detection of SARS-CoV-2 RNA in breastmilk might be the result of retrograde milk flow of infant saliva containing the virus. We feel that this is unlikely; there is no experimental evidence that any virus might be transferred by this route in humans. On the contrary, SARS-CoV-2 contamination from the infant has been excluded in three studies3Buonsenso D Costa C Sanguinetti M et al.Neonatal late onset infection with severe acute respiratory syndrome coronavirus 2.Am J Perinatol. 2020; 37: 869-872Crossref PubMed Scopus (131) Google Scholar, 4Bastug A Hanifehnezhad A Tayman A et al.Virolactia in an asymptomatic mother with COVID-19.Breastfeed Med. 2020; 15: 488-491Crossref PubMed Scopus (45) Google Scholar, 5Tam PCK Ly KM Kernich ML et al.Detectable severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human breast milk of a mildly symptomatic patient with coronavirus disease 2019 (COVID-19).Clin Infect Dis. 2020; (published online May 30.)https://doi.org/10.1093/cid/ciaa673Crossref Scopus (70) Google Scholar reporting viral RNA in milk from mothers, where the infant was either continually COVID-19-negative or separated from the mother, or both. Generally, there are examples of viruses (eg, HIV and human cytomegalovirus) that are shed into breastmilk and might lead to an infection of the neonate, whereas other viruses are shed but typically pose no risk for vertical transmission.6Stiehm ER Keller MA Breast milk transmission of viral disease.Adv Nutr Res. 2001; 10: 105-122Google Scholar Establishing whether either process is relevant for a novel human pathogen requires careful examination. So far, no cases of SARS-CoV-2 transmission via breastfeeding have been reported, and it has not been established if the virus in this body fluid is infectious. Thus, WHO suggests continuing breastfeeding upon maternal SARS-CoV-2 infection. We agree with this recommendation but feel that further research on this topic to protect neonates and to reassure nursing mothers is highly warranted. RG declares funding via a scholarship from the International Graduate School in Molecular Medicine of Ulm University (Ulm, Germany). JAM declares funding from the German Research Foundation; and grants from the Ministry of Science, Research, and the Arts of the State of Baden-Württemberg. FK declares funding from the German Federal Ministry of Education and Research for the project Restrict SARS-CoV-2 and the German Research Foundation for the project CRC1279; and grants from the Ministry of Science, Research, and the Arts of the State of Baden-Württemberg. JM declares funding for the EU 2020 Horizon project Fight-nCoV and the German Research Foundation for the project CRC1279; and by grants from the Ministry of Science, Research, and the Arts of the State of Baden-Württemberg. FR and CC declare no competing interests. Undermining breastfeeding will not alleviate the COVID-19 pandemicBreastfeeding offers numerous immunological, developmental, and psychological advantages to the infant–mother dyad. The risks posed to infant and maternal health through any loss of support for breastfeeding mean that public health messaging during the COVID-19 pandemic should be careful. As academic leads of human milk banks, we are acutely aware of the importance of understanding the risks posed by novel infectious pathogens in human milk and the mitigation of risk to susceptible infants. Full-Text PDF Detection of SARS-CoV-2 in human breastmilkIt remains unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be shed into breastmilk and transmitted to a child through breastfeeding. Recent investigations have found no evidence of SARS-CoV-2 in human breastmilk, but sample sizes were small.1–3 We examined milk from two nursing mothers infected with SARS-CoV-2. Both mothers were informed about the study and gave informed consent. Ethical approval for this case study was waived by the Ethics Committee of Ulm University and all samples were anonymised. Full-Text PDF