2022/01/18 by Paul Krogstad, Deisy Contreras, Hwee L. Ng +5 · 56 citations
Medicine · #COVID-19 Impact on Reproduction #SARS-CoV-2 detection and testing #COVID-19 Clinical Research Studies #Breastfeeding #Virology #Medicine #Breast milk #Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) #Coronavirus #Virus #Infectivity #Subgenomic mRNA #RNA #Reverse transcription polymerase chain reaction #Breast feeding #Transmission (telecommunications) #Coronavirus disease 2019 (COVID-19) #Immunology #Biology #Internal medicine #Infectious disease (medical specialty) #Messenger RNA #Pediatrics #Disease #Gene
paper · pdf · doi:10.1038/s41390-021-01902-y
published in Pediatric Research 92(4), 1140-1145 (Springer Nature)
openalex publication_date 2022/01/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
BACKGROUND: Genomic RNA of severe acute respiratory syndrome-associated coronavirus type 2 (SARS-CoV-2) has been detected in the breast milk of lactating women, but its pathological significance has remained uncertain due to the small size of prior studies. METHODS: Breast milk from 110 lactating women was analyzed by reverse transcription-polymerase chain reaction (285 samples) and viral culture (160 samples). Those containing SARS-CoV-2 viral RNA (vRNA) were examined for the presence of subgenomic RNA (sgRNA), a putative marker of infectivity. RESULTS: Sixty-five women had a positive SARS-CoV-2 diagnostic test, 9 had symptoms but negative diagnostic tests, and 36 symptomatic women were not tested. SARS-CoV-2 vRNA was detected in the milk of 7 (6%) women with either a confirmed infection or symptomatic illness, including 6 of 65 (9%) women with a positive SARS-CoV-2 diagnostic test. Infectious virus was not detected in any culture and none had detectable sgRNA. In control experiments, infectious SARS-CoV-2 could be cultured after addition to breastmilk despite several freeze-thaw cycles, as it occurs in the storage and usage of human milk. CONCLUSIONS: SARS-CoV-2 RNA can be found infrequently in the breastmilk after recent infection, but we found no evidence that breastmilk contains an infectious virus or that breastfeeding represents a risk factor for transmission of infection to infants. IMPACT: This article goes beyond prior small studies to provide evidence that infectious SARS-CoV-2 is not present in the milk of lactating women with recent infection, even when SARS-CoV-2 RNA is detected. Recent SARS-CoV-2 infection or detection of its RNA in human milk is not a contraindication to breastfeeding.