Study finds no evidence of live virus in breast milk of moms with COVID-19A small University of California study finds no evidence that breast milk from mothers infected with SARS-CoV-2 transmits the virus to their babies.The study, published today in Pediatrics Research, involved polymerase chain reaction (PCR) testing of 285 samples and viral culture of 160 samples of breast milk from 110 women with confirmed or suspected COVID-19.The women had donated to a university breast milk biorepository from March to September 2020.
Among them, 65 had confirmed COVID-19, 9 had symptoms but tested negative, and 36 had symptoms but weren't tested.On PCR testing, SARS-CoV-2 subgenomic RNA (sgRNA) was detected in the milk of 7 (6%) women, including 6 of 65 women (9%) with confirmed COVID-19.
sgRNA is not live (infectious) virus but genetic material of unclear significance; some scientists believe it may indicate replicating virus.Testing a second breast milk sample from the 7 women with confirmed COVID-19 1 to 97 days later detected no SARS-CoV-2 sgRNA.
None of the babies had clinical evidence of COVID-19. In lab experiments, the researchers could culture infectious SARS-CoV-2 after adding it to breast milk after repeated freeze–thaw cycles, as may occur in the storage and use of breast milk.The study authors said that while the study was small and may not have captured all factors that indicate the presence of SARS-CoV-2 in breast milk, it is the largest known such study to date and found no evidence that maternal COVID-19 infection rules out breastfeeding.In a Springer news release, lead author Paul Krogstad, MD, said that breast milk is an invaluable source of nutrition for infants. "In our study, we found no evidence that