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- Page navigation anchor for RE: Double insurance of holder pasteurization and human milk itself to guarantee the safety of breastfeedingRE: Double insurance of holder pasteurization and human milk itself to guarantee the safety of breastfeeding
With great interest we read the article by Unger et al in CMAJ [1]. This work highlighted pasteurization by the Holder method (62.5 °C for 30 min) resulted in complete SARS-CoV-2 inactivation in human milk. In this study, the authors did not see complete inactivation of SARS-CoV-2 in media without human milk (positive control) after pasteurization, which differs from the previous report [2]. Actually, we had similar findings with the authors, and SARS-CoV-2 related coronavirus GX_P2V isolated from pangolin [3, 4] could not be completely inactivated after pasteurization at 62.5 °C for 30 minutes.
As shown in the article, the infectivity of SARS-CoV-2 decreased by about 1 log after incubation with human milk for 30 minutes, which leads the author to speculate that breast milk might have some antiviral activity to SARS-CoV-2. Interestingly, our cover story paper recently published in Signal Transduction and Targeted Therapy showed that in Vero E6 and A549 cell lines, the viral entry and replication of SARS-CoV-2 and pangolin coronavirus GX_P2V could be inhibited significantly, and even completely blocked after incubation with human milk [5]. This is consistent with the epidemiological data that even SARS-CoV-2 RNA were detected in some breast milk samples of mothers infected with SARS-CoV-2, no infectious virus particles have been found to date [6, 7].
Further mechanistic study showed that the whey protein in breast milk could not only block the binding of ACE2...
Show MoreCompeting Interests: None declared.References
- 4. Fan HH, Wang LQ, Liu WL, et al. Repurposing of clinically approved drugs for treatment of coronavirus disease 2019 in a 2019-novel coronavirus-related coronavirus model. Chin Med J (Engl) 2020. 133:1051-1056.
- 5. Fan H, Hong B, Luo Y, et al. The effect of whey protein on viral infection and replication of SARS-CoV-2 and pangolin coronavirus in vitro. Signal Transduct Target Ther 2020. 5:275.
- 6. Chambers C, Krogstad P, Bertrand K, et al. Evaluation for SARS-CoV-2 in Breast Milk From 18 Infected Women. JAMA 2020. 324:1347-1348.
- 7. Centeno-Tablante E, Medina-Rivera M, Finkelstein JL, et al. Transmission of SARS-CoV-2 through breast milk and breastfeeding: a living systematic review. Ann N Y Acad Sci 2020. doi:10.1111/nyas.14477.
- 8. WHO Breastfeeding and COVID-19 for health care workers. May 12, 2020. https://www.who.int/docs/default-source/maternal-health/faqs-breastfeeding-and-covid-19.pdf?sfvrsn=d839e6c0_5.
- Page navigation anchor for RE: Tangible Applications for SARS-CoV-2 Viral CultureRE: Tangible Applications for SARS-CoV-2 Viral Culture
The ability to culture live virus and thereafter examine for SARS-CoV-2 viability is a welcome and necessary tool, and the application of the same as detailed by Unger et al. provides tangible data.(1) All too often the presence and/or quantitation of virus for various investigations has been published after utilization of viral RNA assays only. There are several niche contexts where the determination of live virus is valuable.
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One such application in wanting could be the determination of viable SARS-CoV-2 in public swimming pool waters. Swimming pool water decontamination usually includes 2-4 ppm free chlorine. The latter may be augmented by UV treatment or by other chemical additives depending on the context and often depending on the age of the pool systems. A dilutional effect on shed virus from an infected individual in such water systems is likely to occur but the prospects of encountering live virus remain. From a disinfection perspective, however, 2-4 ppm free chlorine would likely have little antiviral activity for coronaviruses let alone SARS-CoV-2 in particular. Most efficacy studies of hypochlorite use working dilutions in the range of 50-2000 ppm.(2-5) Close to this range, slightly less at 10 ppm had inefficacy against surrogate coronaviruses.(3) Antiviral activity can be considerably reduced for virus on steel carriers or in the presence of a bioload.(4,5) It remains to be determined if viable SARS-CoV-2 may survive in such waters.
As Canadian p...Competing Interests: None declared.References
- 1. Sharon Unger, Natasha Christie-Holmes, Furkan Guvenc, et al. Holder pasteurization of donated human milk is effective in inactivating SARS-CoV-2. CMAJ 2020;10.1503/cmaj.201309.
- 2. Cimolai N. Environmental and decontamination issues for human coronaviruses and their potential surrogates. J Med Virol 2020 Jun 12;10.1002/jmv.26170. doi: 10.1002/jmv.26170.
- 3. Saknimit M, Inatsuki I, Sugiyama Y, Yagami K. Virucidal efficacy of physico-chemical treatments against coronaviruses and parvoviruses of laboratory animals. Exp Anim 1988;37(3):341-5.
- 4. Hulkower RL, Casanova LM, Rutala WA, Weber DJ, Sobsey MD. Inactivation of surrogate coronaviruses on hard surfaces by health care germicides. Am J Infect Control 2011;39(5):401-7.
- 5. Bowman AS, Nolting JM, Nelson SW, Bliss N, Stull JW, Wang Q, et al. Effects of disinfection on the molecular detection of porcine epidemic diarrhea virus. Vet Microbiol 2015;179(3-4):213-8.