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Disclosures: Krogstad reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
January 20, 2022
1 min read

Study finds no evidence of SARS-CoV-2 transmission via breast milk

Disclosures: Krogstad reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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A small study found no evidence that mothers infected with SARS-CoV-2 transmitted the virus to their babies through breast milk, affirming previous studies.

“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,” Paul A. Krogstad, MD, a professor in the departments of pediatrics and pharmacology at UCLA Health, and colleagues wrote in Pediatric Research.

Black infant being breastfed
A new study found no evidence of infectious SARS-CoV-2 in the breast milk of mothers with a confirmed infection.
Photo source: Adobe stock.

In the new study, Krogstad and colleagues analyzed the breast milk of 110 women throughout the U.S., most of them white, aged in their mid-20s to mid-40s. Among them, 65 women had a confirmed SARS-CoV-2 infection, nine women had symptoms but tested negative for SARS-CoV-2 and the remaining women had symptoms but were not tested.

“The collection of breast milk samples was not directly observed and we relied on the maternal report of SARS-CoV-2 test results, symptoms and treatments received,” the researchers wrote. “However, all participants completed a semi-structured interview guided by trained study staff who prompted for specifics with the aid of a calendar.”

Krogstad and colleagues reported that among all the women, SARS-CoV-2 viral RNA was found in the breast milk of 6% of the women with either confirmed infection or symptomatic illness and 9% of the women with a positive SARS-CoV-2 diagnostic test. Infectious SARS-CoV-2 was not detected in any of the cultures, and none showed signs of subgenomic RNA, an indicator of SARS-CoV-2 replication, according to the researchers.

“To our knowledge, this study represents the largest number of breast milk samples analyzed to date from women with recent SARS-CoV-2 infection,” the researchers wrote. “Nonetheless, even this size may have been too small to permit the identification of factors that would predict the presence of SARS-CoV-2 RNA in breast milk.”

Kroger said in a press release that the study suggests “breastfeeding is not likely to be a hazard.”


COVID-19: Small study found no evidence of transmitting virus through breastfeeding. Published Jan. 18, 2022. Accessed Jan. 18, 2022.

Krogstad P, et al. Pediatr Res. 2022;doi:10.1038/s41390-021-01902-y.