SARS‐CoV ‐2 in human milk is inactivated by Holder pasteurisation but not cold storage

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Abstract

As the COVID‐19 pandemic evolves, human milk banks world‐wide continue to provide donor human milk to vulnerable infants who lack access to mother's own milk. Under these circumstances, ensuring the safety of donor human milk is paramount, as the risk of vertical transmission of SARS‐CoV‐2 is not fully understood. Here, we investigate the inactivation of SARS‐CoV‐2 in human milk by pasteurisation and the stability of SARS‐CoV‐2 in human milk under cold storage.

Methods

SARS‐CoV‐2 was experimentally inoculated into human milk samples from healthy donors or into a control medium. Triplicates of each sample were layered onto uninfected cells after Holder pasteurisation (63°C for 30 min), heating to 56°C for 30 min, or after 48 h of storage at 4°C or −30°C. Infectious titres of virus were determined at 72 h post‐infection by endpoint titration.

Results

Following heating to 63°C or 56°C for 30 min, replication competent (i.e. live) SARS‐CoV‐2 was undetected in both human milk and the control medium. Cold storage of SARS‐CoV‐2 in human milk (either at 4°C or −30°C) did not significantly impact infectious viral load over a 48 h period.

Conclusion

SARS‐CoV‐2 is effectively inactivated by Holder pasteurisation, suggesting that existing milk bank processes will effectively mitigate the risk of transmission of SARS‐COV‐2 to vulnerable infants through pasteurised donor human milk. The demonstrated stability of SARS‐CoV‐2 in refrigerated or frozen human milk may assist in the development of guidelines around safe expressing and storing of milk from COVID‐19 infected mothers.

Article activity feed

  1. SciScore for 10.1101/2020.06.18.20134395: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Experimental Models: Cell Lines
    SentencesResources
    Endpoint titration of samples was performed on Vero cells in sextuplicate, and the 50% tissue culture infectious dose (TCID50) determined at 72 hours post-infection using standard methods.
    Vero
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).


    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.


    Results from Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).


    Results from JetFighter: We did not find any issues relating to colormaps.


    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.