SARS-CoV-2 genome and antibodies in breastmilk: a systematic review and meta-analysis.


Zhu F(1)(2), Zozaya C(1)(2), Zhou Q(1)(2), De Castro C(3), Shah PS(4)(2).
Author information:
(1)Department of Pediatrics, Sinai Health System, Toronto, Ontario, Canada.
(2)Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
(3)Sidney Liswood Health Sciences Library, Sinai Health System, Toronto, Ontario, Canada.
(4)Department of Pediatrics, Sinai Health System, Toronto, Ontario, Canada [Email]


OBJECTIVE: To systematically review and meta-analyse the rate of SARS-CoV-2 genome identification and the presence of SARS-CoV-2 antibodies in breastmilk of mothers with COVID-19. DESIGN: A systematic review of studies published between January 2019 and October 2020 without study design or language restrictions. SETTING: Data sourced from Ovid Embase Classic+Embase, PubMed, Web of Science, Scopus, relevant bibliographies and the John Hopkins University COVID-19 database. PATIENTS: Mothers with confirmed COVID-19 and breastmilk tested for SARS-CoV-2 by RT-PCR or for anti-SARS-CoV-2 antibodies. MAIN OUTCOME MEASURES: Presence of SARS-CoV-2 genome and antibodies in breastmilk. RESULTS: We included 50 articles. Twelve out of 183 women from 48 studies were positive for SARS-CoV-2 genome in their breastmilk (pooled proportion 5% (95% CI 2% to 15%; I2=48%)). Six infants (50%) of these 12 mothers tested positive for SARS-CoV-2, with one requiring respiratory support. Sixty-one out of 89 women from 10 studies had anti-SARS-CoV-2 antibody in their breastmilk (pooled proportion 83% (95% CI 32% to 98%; I2=88%)). The predominant antibody detected was IgA. CONCLUSIONS: SARS-CoV-2 genome presence in breastmilk is uncommon and is associated with mild symptoms in infants. Anti-SARS-CoV-2 antibodies may be a more common finding. Considering the low proportion of SARS-CoV-2 genome detected in breastmilk and its lower virulence, mothers with COVID-19 should be supported to breastfeed.