Question & Answer

Does disinfecting surfaces or objects prevent the spread of COVID-19?

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  • Images in the media of large-scale disinfection/sanitisation of public spaces across countries affected by the COVID-19 pandemic have led to an increased use of disinfectants/sanitisers.
  • The major transmission route for the COVID-19 virus is through droplets generated when a person coughs or sneezes. These droplets can be breathed in by, or land on, others nearby and this is why following the advice on physical distancing is so important.  Droplets may also land on nearby surfaces that others then touch. So when people touch their eyes, nose or mouth after touching these surfaces, they can potentially become infected.
  • Although the virus that causes COVID-19, SARS CoV-2, is a new virus and we are still learning about how it behaves, there is evidence from other coronaviruses that is helpful in guiding advice about the use of cleaning products and disinfectants.
  • We are not certain how long SARS-CoV-2 can survive on surfaces, but as a guide, a recent study found that the coronavirus can survive for up to 4 hours on copper, up to 24 hours on cardboard and up to 72 hours on plastic and stainless steel.
  • Common household disinfectants, including soap or diluted bleach solutions can effectively neutralise coronaviruses on indoor surfaces and objects.
  • The Centers for Disease Control and Prevention CDC in the United States released recommendations on cleaning and disinfection for households, specifically aimed at households with people who have been in contact with a person confirmed with COVID-19, or who have been infected with COVID-19.
    • Cleaning refers to removing of germs, dirt, and impurities from surfaces. It does not kill germs, but by removing them, it lowers their numbers and the risk of spreading infection.
    • Disinfecting refers to using chemicals to kill germs on surfaces. This process does not necessarily clean dirty surfaces, but by killing germs on a surface after cleaning, it can further lower the risk of spreading infection.
  • The World Health Organization recommends that ‘High-touch surfaces’  in households – including door handles, kitchen and food preparation areas, countertops, bathroom surfaces, touchscreen personal devices and personal computer keyboards – should be prioritised when cleaning. They recommend that ‘surfaces should always be cleaned with soap and water or a detergent to remove organic matter first, followed by disinfection.’
  • The World Health Organization advice is to thoroughly wash your hands before and after shopping, and again after unpacking and storing your shopping.
  • To protect yourself and others from coronavirus, please follow public health advice and wash your hands properly and often.

Things to Remember

Reviewers

  • Lead Researcher: Dr Sonja Khan, HRB Clinical Research Facility, University Hospital Galway and NUI Galway
  • Reviewed by: Elaine Finucane, HRB-Trials Methodology Research Network, School of nursing and Midwifery, NUI Galway.
  • Evidence Advisor: Dr Maureen Kelly, College of Medicine, Nursing and Health Sciences NUI Galway
  • Evidence Advisor: Casey Donaghey, PPI Ignite, NUI Galway.
  • Journalist Advisor: Dr Claire O’Connell, Contributor, The Irish Times.