Many may think you need to be in direct contact with someone who has COVID-19 to catch the virus. But COVID-19 may persist for several days on surfaces. This known fact led Kings College London to classify this misunderstanding as a dangerous myth.

In February 2020 a review searched the global literature to identify studies looking at the persistence of all known coronaviruses on inanimate surfaces like plastic or glass. Coronoviruses include SARS-CoV responsible for the 2002 SARS outbreak originating in southern China, MERS-CoV responsible for the Middle East Respiratory Syndrome of 2012, and SARS-CoV-2, this new coronavirus. These past studies of other coronaviruses show that they can persist on surfaces for up to 9 days but can be effectively removed by surface disinfection.

These data emphasise the need not only for surface hygiene but also regular handwashing as a key infection control measure. This will protect individuals against viruses they may have picked up through contact with inanimate surfaces, but also remove any respiratory droplets they may have on their hands (e.g. from coughing and sneezing) that could transmit the virus to others.

Where did the story come from?

The systematic review on persistence of coronaviruses on inanimate surfaces was published in February 2020 in The Journal of Hospital Infection.

King’s College London cited this publication in support of their classification of the idea that COVID-19 was contracted only through direct contact with an infected person, as a dangerous myth.

What is the basis for the claim?

The review searched for studies published up to 28th January 2020 on coronaviruses and their persistence on surfaces or materials and/or deactivation by disinfection. The researchers identified 22 studies, covering SARS-CoV, MERS-CoV and other human coronavirus strains (e.g. HCoV strain 229E) which commonly circulate among the population causing mild cold-like symptoms.

How long viruses persisted on surfaces depended on the specific virus, viral load, type of surface (e.g. plastic, glass, metal), temperature and humidity. For example HCoV-229E persisted on different surfaces from a few hours to 9 days, with greater persistence at higher humidity. SARS-CoV was shown to persist at room temperature for around 4 or 5 days on most surfaces, while one analysis of MERS-CoV showed it survived on plastic for 48 hours at 20◦C reducing to 8-24 hours at 30◦C. They found that disinfects like ethanol (78-95%), hydrogen peroxide (0.5%) and sodium hypochlorite (>0.21% concentration) inactivated coronavirus after 1 minute contact time.

The various factors influencing viral persistence make it difficult to be certain yet exactly how long COVID-19 may survive on different surfaces and under different conditions.

Together these studies highlight the value of surface disinfection, particularly of shared items, such as supermarket trollies, and of regular handwashing.

What do trusted sources say?

The WHO advises cleaning hands frequently and thoroughly, using soap and water or alcohol-based hand sanitisers as the best way to protect yourself and others against COVID-19. They also advise that handwashing gives you more protection than wearing gloves, as you can still contaminate the gloves, and then transfer this contamination to your face.

CDC also advises daily cleaning and disinfection of frequently-touched surfaces. They suggest cleaning with soap and water (if surfaces are visibly contaminated) prior to use of household disinfectant.

 

Citation

  1. Kampf G, Todt D, Pfaender S, Steinmann E. Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents. Journal of Hospital Infection. 2020 Feb 6.
  2. King’s College London. Blog: The ten most dangerous coronavirus myths debunked.

 

Reading list

  1. World Health Organisation. Advice for the public.
  2. Centers for Disease Control. How to protect yourself and others.
  3. New Scientist. Types of Coronavirus