Stability of SARS-CoV-2 in different environmental conditions – Authors' reply
Authors: Alex W H Chin, Leo L M Poon
Journal: The Lancet Microbe (2020)

Reza Dehbandi and Mohammad Ali Zazouli query our Correspondence about the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different environmental conditions.1Chin AWH Chu JTS Perera MRA et al.Stability of SARS-CoV-2 in different environmental conditions.Lancet Microbe. 2020; 1: e10Summary Full Text Full Text PDF PubMed Scopus (1098) Google Scholar Rather than testing the cleansing properties of the studied disinfectants, the objective of our work was to reveal the virucidal effects of these disinfectants, specifically their ability to inactivate SARS-CoV-2. We entirely agree with Dehbandi and Zazouli that hand hygiene is a key topic that can help to reduce SARS-CoV-2 transmission. But we want to highlight that we had no intention to use our data to comment on hand hygiene policy. Regarding hand hygiene policy against COVID-19, the interim recommendations by WHO would be a great place to start. Plain soap is regarded as a low-level disinfectant against enveloped virus.2Australian Veterinary Emergency Plan (AUSVETPLAN)Operational procedures manual: decontamination (version 3.2, 2008).http://www.fao.org/ag/againfo/commissions/docs/training/material/AusVet/plan-2009.pdfDate: June 10, 2018Date accessed: May 21, 2020Google Scholar Our findings showed the disinfectant property of plain soap solution against SARS-CoV-2, albeit with lower efficiency compared with the other studied disinfectants. Using soap solution to disinfect SARS-CoV-2 may require longer contact time to achieve the same level of disinfection. Such information would be useful to establish evidence-based SARS-CoV-2 disinfection procedures in settings with extremely limited sources. To decontaminate a surface, we need to apply a disinfectant at an effective concentration and allow an adequate contact time. The selected sampling time points in our study (5, 15, and 30 min) are similar to those normally used in routine surface or instrument decontamination procedures (ie, 5 min or more).2Australian Veterinary Emergency Plan (AUSVETPLAN)Operational procedures manual: decontamination (version 3.2, 2008).http://www.fao.org/ag/againfo/commissions/docs/training/material/AusVet/plan-2009.pdfDate: June 10, 2018Date accessed: May 21, 2020Google Scholar, 3Rutala WA Weber DJ Guideline for disinfection and sterilization in healthcare facilities, 2008 (update: May 2019).https://www.cdc.gov/infectioncontrol/pdf/guidelines/disinfection-guidelines-H.pdfDate accessed: May 21, 2020Google Scholar, 4Rabenau HF Kampf G Cinatl J Doerr HW Efficacy of various disinfectants against SARS coronavirus.J Hosp Infect. 2005; 61: 107-111Summary Full Text Full Text PDF PubMed Scopus (215) Google Scholar At the time we started our experiment (Feb 20, 2020), there was a scarcity of evidence-based information on the effectiveness of various disinfectants to inactivate SARS-CoV-2. Although some work has been published on disinfection of other coronaviruses, whether this could be applied to SARS-CoV-2 had not been established at that time. We reasoned that such information would be extremely useful to control COVID-19. Therefore, we intended to show whether different, commonly used disinfectants and disinfection procedures are effective to inactivate SARS-CoV-2 on contaminated objects. The two different working concentrations of household bleach are recommended for general disinfection (1:99 dilution) and disinfection when an obvious contaminant is seen (1:49 dilution).5Hong Kong Centre for Health ProtectionInfection Control BranchAdvice on household disinfection at the peak season of seasonal influenza (update: December 2018).https://www.chp.gov.hk/files/pdf/advice_on_household_disinfection_at_the_height_of_influenza_season.pdfDate accessed: May 21, 2020Google Scholar Our research showed that household bleach at both working concentrations are effective against SARS-CoV-2. Comparing the effectiveness between these disinfectants was not our primary goal at that time. We declare no competing interests. Stability of SARS-CoV-2 in different environmental conditionsWe feel the need to address several errors in the findings presented in the Correspondence by Alex W H Chin and colleagues.1 Some results of this research challenge the current hand hygiene programmes recommended by different public health authorities, and we think that caution is required when applying those results to protect human health during infectious disease outbreaks, including the outbreak of COVID-19. Full-Text PDF Open AccessStability of SARS-CoV-2 in different environmental conditionsWe previously reported the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different clinical samples.1 This virus can be detected on different surfaces in a contaminated site.2 Here, we report the stability of SARS-CoV-2 in different environmental conditions. Full-Text PDF Open Access