SARS-CoV-2 Virus Stability and Disinfecting
Posted:
2020-04-02
Two recent studies have emerged on the persistence of the coronavirus on various surfaces (1,2). Using an in vitro study, Van Doremalen et al. examined how long SARS-CoV-2 virus (i.e. the virus that causes COVID-19*) remained viable on four surfaces (cardboard, plastic, stainless steel and copper) for varying lengths of time (1). At room temperature and 40% humidity, viable SARS-CoV-2 viruses were detectable up to 24 hours on cardboard and up to 72 hours on stainless steel and plastic. The virus was not viable after four hours on copper.
Kampf et al. reported a review on coronavirus persistence on surfaces and materials (2). While this second study examined coronaviruses, it did not specifically study the SARS-CoV-2 virus; the authors suggest that they expect the persistence and inactivation of this new coronavirus are likely similar. They found that coronaviruses can remain potentially infectious from two hours up to nine days on various materials. At higher air temperatures of 30 to 40 °C, persistence was reduced compared to room temperatures. The studied viruses were stable (≥28 days) at refrigerator temperature, 4 °C. Humidity influenced persistence, as coronaviruses were less stable at 30% relative humidity compared to 50% relative humidity. The researchers also found that biocidal agents including 62-71% ethanol, 0.5% hydrogen peroxide or 0.2% sodium hypochlorite (bleach - preparation instructions below) used for disinfecting inactivated coronaviruses within one minute. Other biocidal agents were noted to be less effective.
Various organizations have now recommended guidelines based on the results of the first study. These include:
- Wash your hands thoroughly with soap and water for 20 seconds before and after preparing and eating food, using the washroom, after sneezing or coughing (3). Although the risk is low, if you are concerned or if you or someone in the household is of high risk, wash your hands after handling anything that might be contaminated such as cardboard, plastic and stainless steel (4).
- Disinfect hard surfaces daily including high touch areas such door handles, light switches, counter tops, tables, keyboards, toys, phones and TV remotes using ER-approved disinfectant (3).
- Refer to Health Canada’s Hard Surface Disinfectants and Hand Sanitizers (COVID-19) for instructions and for a list of effective disinfectants. Be sure to read manufacturers’ directions on the labels of the disinfectant cleaning product as many of these need to remain in contact with the surface for a period of time (e.g. 30 seconds) to be effective (e.g. do not just spray on and wipe off) (5).
- As these products are currently hard to find because of the COVID-19 pandemic, a solution of diluted bleach can also be used as per instructions on the label of the bleach container. For 5% sodium hypochlorite bleach (the usual concentration sold in stores) use 5 mL (1 tsp) per 250 mL (1 cup) of water or 20 mL (4 tsp) per 1 litre (4 cups) of water to make a 0.2% solution (5).
- Cleaning products remove germs and dirt, lowering their numbers and reducing the risk of spreading infections (5). Products with disinfectants kill germs.
*Note: SARS-CoV-2 is the name of the virus. COVID-19 is the disease the virus causes.
References
- van Doremalen N, Bushmaker T, Morris DH, Holbrook MG, Gamble A, Williamson BN, et al. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. N Engl J Med. 2020 Mar 17. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/?term=32182409
- Kampf G, Todt D, Pfaender S, Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. J Hosp Infect. 2020 Mar;104(3):246-51. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/?term=32035997
- Health Canada. Coronavirus Disease (COVID-19): prevention and risks. 2020 Apr 1. Available from: https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/prevention-risks.html?topic=tilelink
- Harvard T.H. Chan. School of Public Health. Food Safety, nutrition, and wellness during COVID-19. 2020 Mar 25. Available from https://www.hsph.harvard.edu/nutritionsource/2020/03/25/food-safety-nutrition-and-wellness-during-covid-19/
- Health Canada. Hard surface disinfectants and hand sanitizers (COVID-19). 2020 Mar 30. Available from https://www.canada.ca/en/health-canada/services/drugs-health-products/disinfectants/covid-19.html