SARS-CoV-2 Infection Among Maternal-Infant Dyads in Ontario, Canada | Infectious Diseases | JAMA Network Open | JAMA Network
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Figure.  Flow Diagram for Perinatal SARS-CoV-2 Testing Among New Mother-Infant Pairs for Births Occurring in Ontario During the COVID-19 Pandemic Period (February 1 to October 31, 2020)
Flow Diagram for Perinatal SARS-CoV-2 Testing Among New Mother-Infant Pairs for Births Occurring in Ontario During the COVID-19 Pandemic Period (February 1 to October 31, 2020)

Cell sizes representing fewer than 6 mothers or infants have been suppressed to reduce the risk of reidentification.

Table.  Characteristics of Ontario Newborns Born Between February 1 and October 31, 2020, and Tested for SARS-CoV-2
Characteristics of Ontario Newborns Born Between February 1 and October 31, 2020, and Tested for SARS-CoV-2
1.
Edlow  AG, Li  JZ, Collier  AY,  et al.  Assessment of maternal and neonatal SARS-CoV-2 viral load, transplacental antibody transfer, and placental pathology in pregnancies during the COVID-19 pandemic.   JAMA Netw Open. 2020;3(12):e2030455. doi:10.1001/jamanetworkopen.2020.30455 PubMedGoogle Scholar
2.
Cavicchiolo  ME, Trevisanuto  D, Lolli  E,  et al.  Universal screening of high-risk neonates, parents, and staff at a neonatal intensive care unit during the SARS-CoV-2 pandemic.   Eur J Pediatr. 2020;179(12):1949-1955. doi:10.1007/s00431-020-03765-7 PubMedGoogle ScholarCrossref
3.
Stuebe  A.  Should infants be separated from mothers with COVID-19? first, do no harm.   Breastfeed Med. 2020;15(5):351-352. doi:10.1089/bfm.2020.29153.ams PubMedGoogle ScholarCrossref
4.
Provincial Council for Maternal and Child Health. Maternal-neonatal COVID-19 general guideline. Updated October 22, 2020. Accessed February 1, 2021. https://www.pcmch.on.ca/wp-content/uploads/2020/10/MatNeo-COVID-19-Guide_OCT222020.pdf
5.
Chung  H, Fung  K, Ferreira-Legere  LE,  et al. COVID-19 laboratory testing in Ontario: patterns of testing and characteristics of individuals tested, as of April 30, 2020. ICES. Accessed September 30, 2020. https://www.ices.on.ca/Publications/Atlases-and-Reports/2020/COVID-19-Laboratory-Testing-in-Ontario
6.
Ronchi  A, Pietrasanta  C, Zavattoni  M,  et al.  Evaluation of rooming-in practice for neonates born to mothers with severe acute respiratory syndrome coronavirus 2 infection in Italy.   JAMA Pediatr. 2021;175(3):260-266. doi:10.1001/jamapediatrics.2020.5086 PubMedGoogle ScholarCrossref
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    Research Letter
    Infectious Diseases
    August 9, 2021

    SARS-CoV-2 Infection Among Maternal-Infant Dyads in Ontario, Canada

    Author Affiliations
    • 1Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
    • 2ICES, Toronto, Ontario, Canada
    JAMA Netw Open. 2021;4(8):e2120150. doi:10.1001/jamanetworkopen.2021.20150
    Introduction

    Although reports of COVID-19 infection among infants are rare,1-3 many professional bodies have issued recommendations for the screening and management of neonates.2-4 Since April 1, 2020, polymerase chain reaction testing within 24 hours of birth has been recommended in Ontario—Canada’s largest province—for all infants born to mothers with confirmed SARS-CoV-2 infection at delivery.2 For this study, population-based birth registry, laboratory, and public health case data were assessed to describe SARS-CoV-2 testing outcomes among infants born during the COVID-19 pandemic and their mothers.

    Methods

    We created a birth cohort of all infants delivered alive in Ontario during the COVID-19 pandemic period as identified either in the provincial hospital birth registry, MOMBABY, or SARS-CoV-2 laboratory data (for tested infants not yet registered in the birth registry). Mother-infant dyads were identified from MOMBABY records. The use of data in this project was authorized under section 45 of Ontario’s Personal Health Information Protection Act and exempt from research ethics board review. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.

    We used linked administrative health, laboratory, and COVID-19 case management databases to identify SARS-CoV-2 diagnostic tests among all infants born in-hospital between February 1 and October 31, 2020, and maternal testing outcomes between January 15 and October 31, 2020.5 We summarized testing outcomes for maternal-infant dyads in the perinatal and postnatal period using SAS, version 9.4 (SAS Institute Inc). Specifically, we described the frequency of completed and positive tests reported among dyads and summarized the characteristics of infants tested for SARS-CoV-2. See the eMethods in the Supplement for additional details regarding these data sources.

    Results

    In this cohort of 96 689 infants, 6176 (6.4%) had a record of receiving a diagnostic test for SARS-CoV-2; 1724 (1.8%) were tested perinatally (ie, within the first 2 weeks of life). Only 177 infants (0.1% of births; 2.9% of those tested) were positive for SARS-CoV-2 (Table). Median age at detection was 108 days (interquartile range, 50-189 days); fewer than 12 infections in infants (suppressed to maintain confidentiality) were identified perinatally. Of 177 infants infected with SARS-CoV-2, 90 (50.9%) had mothers who tested positive for SARS-CoV-2 at some point during the pandemic; however, only 6 (3.4%) were perinatal cases.

    Only 156 of 82 484 delivering mothers (0.2%) were known to be positive for SARS-CoV-2 infection within 2 weeks of delivery. Only 6 infants (3.9%) born to these positive mothers were known to have acquired SARS-CoV-2 perinatally, and another 9 (5.8%) had positive tested results later in early infancy (Figure). Of note, 20 of 43 infants (46.5%) born to mothers known to be infected within 2 weeks of delivery had no record of being tested within 24 hours, as recommended by provincial guidelines.

    Discussion

    To our knowledge, this is the first population-based report of SARS-CoV-2 testing among a newborn cohort. The findings of this cohort study provide further evidence suggesting that perinatal transmission of, and early-life infection with, SARS-CoV-2 is rare. These findings align with an early report of a universal screening program for high-risk neonates and their parents2 and 2 recent studies from the US1 and Italy,6 none of which found evidence of vertical transmission.

    Ontario’s current provincial guidelines do not recommend separation for newborns born to mothers confirmed to have SARS-CoV-2, although distancing and masks are recommended.4 These measures appear to have effectively limited transmission to newborns, without imposing potential harms through separation.3 It is not clear to what degree provincial testing guidelines were followed; 20 of 43 infants born to mothers known to be infected near delivery had no record of being tested within 24 hours. However, this evaluation is beyond the scope of our study.

    Despite the strengths of its population-based nature, this study has limitations. Most notably, we were unable to link all maternal-newborn dyads, lacked data on stillbirths and pregnancy losses, and could not explicitly investigate vertical transmission. Furthermore, universal testing of new mothers and neonates is currently not recommended—consequently, leading to underestimation of the true incidence. In addition, we are unable to identify whether other household members had SARS-CoV-2, which likely is an important contributor to transmission once a mother-infant dyad is discharged. The findings of this cohort study suggest that SARS-CoV-2 infection in early infancy is rare; however, ongoing surveillance is required to ensure the continued protection of newborns from SARS-CoV-2 and its variants.

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    Article Information

    Accepted for Publication: June 1, 2021.

    Published: August 9, 2021. doi:10.1001/jamanetworkopen.2021.20150

    Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Fitzpatrick T et al. JAMA Network Open.

    Corresponding Author: Astrid Guttmann, MDCM, MSc, ICES, G1 06, 2075 Bayview Ave, Toronto, ON M4N 3M5, Canada (astrid.guttmann@ices.on.ca).

    Author Contributions: Mr Wilton and Dr Guttmann had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

    Concept and design: Fitzpatrick, Chung, Guttmann.

    Acquisition, analysis, or interpretation of data: All authors.

    Drafting of the manuscript: Fitzpatrick, Guttmann.

    Critical revision of the manuscript for important intellectual content: Fitzpatrick, Wilton, Chung.

    Statistical analysis: Fitzpatrick, Wilton.

    Administrative, technical, or material support: Fitzpatrick, Guttmann.

    Supervision: Guttmann.

    Conflict of Interest Disclosures: Dr Guttmann reported receiving funding through ICES from the Ontario Ministry of Health (MOH) to ICES (formerly, the Institute for Clinical Evaluative Sciences), including specific funding for COVID-19–related work during the conduct of the study. No other disclosures were reported.

    Funding/Support: This study was supported by ICES, which is funded by the Ontario MOH and MLTC, as well as the Ontario Health Data Platform (OHDP), a Province of Ontario initiative to support Ontario’s ongoing response to COVID-19 and its related effects.

    Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

    Disclaimer: The opinions, results, and conclusions are those of the authors and are independent from the funding source. No endorsement by ICES, the Ontario MOH or MLTC, the OHDP and its partners, or the Province of Ontario is intended or should be inferred.

    Additional Contributions: The authors thank Public Health Ontario for access to case level data from the integrated Public Health Information System (iPHIS); Case and Contact Management System (CCM) Plus, and COVID-19 laboratory data as well as assistance with data interpretation. They also thank the staff of Ontario’s public health units who are responsible for COVID-19 case and contact management and data collection within iPHIS/CCM Plus.

    Additional Information: Parts of this report are based on data and information compiled and provided by the Ontario MOH, the Canadian Institute for Health Information, and Public Health Ontario.

    References
    1.
    Edlow  AG, Li  JZ, Collier  AY,  et al.  Assessment of maternal and neonatal SARS-CoV-2 viral load, transplacental antibody transfer, and placental pathology in pregnancies during the COVID-19 pandemic.   JAMA Netw Open. 2020;3(12):e2030455. doi:10.1001/jamanetworkopen.2020.30455 PubMedGoogle Scholar
    2.
    Cavicchiolo  ME, Trevisanuto  D, Lolli  E,  et al.  Universal screening of high-risk neonates, parents, and staff at a neonatal intensive care unit during the SARS-CoV-2 pandemic.   Eur J Pediatr. 2020;179(12):1949-1955. doi:10.1007/s00431-020-03765-7 PubMedGoogle ScholarCrossref
    3.
    Stuebe  A.  Should infants be separated from mothers with COVID-19? first, do no harm.   Breastfeed Med. 2020;15(5):351-352. doi:10.1089/bfm.2020.29153.ams PubMedGoogle ScholarCrossref
    4.
    Provincial Council for Maternal and Child Health. Maternal-neonatal COVID-19 general guideline. Updated October 22, 2020. Accessed February 1, 2021. https://www.pcmch.on.ca/wp-content/uploads/2020/10/MatNeo-COVID-19-Guide_OCT222020.pdf
    5.
    Chung  H, Fung  K, Ferreira-Legere  LE,  et al. COVID-19 laboratory testing in Ontario: patterns of testing and characteristics of individuals tested, as of April 30, 2020. ICES. Accessed September 30, 2020. https://www.ices.on.ca/Publications/Atlases-and-Reports/2020/COVID-19-Laboratory-Testing-in-Ontario
    6.
    Ronchi  A, Pietrasanta  C, Zavattoni  M,  et al.  Evaluation of rooming-in practice for neonates born to mothers with severe acute respiratory syndrome coronavirus 2 infection in Italy.   JAMA Pediatr. 2021;175(3):260-266. doi:10.1001/jamapediatrics.2020.5086 PubMedGoogle ScholarCrossref
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