How Long Does COVID-19 Survive On Surfaces?

COVID-19 Transmission On Surfaces

The coronavirus disease 2019 (COVID-19), is the cause of an acute respiratory condition and poses a global threat to public health.^[1] Person-person transmission of the virus has been documented in hospital and family settings,^[2] and more specifically, a publication suggests that transmission via both aerosol particles and surfaces is plausible.^[3] In addition, COVID-19 has been found in the stool, and so, a fecal-oral route of transmission is also hypothesized.^[4]

Minimizing COVID-19 Exposure and Surface Transmission
Currently, there is no specific treatment for COVID-19, and a vaccine is not yet available.^[5] However, we can prevent the spread of the virus by taking certain precautions and measures, such as physical distancing, regular hand washing, and avoiding contact with the nose, eyes, and mouth. It is also important to consider contact with high-touch surfaces that may contain the virus. This article will outline 10 surfaces regularly contacted, and how to best proceed, given the current state of evidence where possible.

Disinfectants
The World Health Organization emphasizes the importance of thorough cleaning and disinfection in health care settings,^[6] and though limited research is available, disinfection strategies may be useful to implement at home in order to minimize contact with the virus. A recent review of various coronaviruses suggests the use of 0.1% sodium hypochlorite, 0.5% hydrogen peroxide, or 62-71% ethanol as surface disinfectants are able to significantly reduce coronavirus infectivity within 1 minute of exposure.^[7] The authors expect that these disinfectants can offer the same level of efficacy with the COVID-19 strain of coronaviruses.

The general recommendations from this review are summarized in Table 1, and a more in-depth comparison of different biocidal agents can be found in Table 3.

Evidence for 10 Surfaces On whcih COVID-19 can survive

Metal Doorknobs, Keys, Elevator Buttons
These surfaces and items are important to consider as the coronavirus has been found to survive on metals. However, the viability seems to vary with the type of metal.^[3] For example, the virus was viable and detected on stainless steel after 72 hours, whereas no viable virus was detected on copper after 4 hours of application.^[3]

Toothbrushes
Considering the virus has been found in saliva,^[8] and has been found viable on plastic after 72 hours of application,^[3] it is possible for toothbrushes to harbor the coronavirus. Though there is limited evidence for how to best proceed, it may be helpful to replace toothbrushes if you have been exposed to COVID-19 or are experiencing symptoms. It may also be important to disinfect the handle of the toothbrush and engage in proper handwashing before and after brushing teeth. Additionally, it may be best to avoid a communal toothbrush holder or avoid placement in proximity if living with others, especially if living with seniors.

Eyeglasses
According to the American Academy of Ophthalmology, eyeglasses or sunglasses can act as a shield from respiratory droplets; however, this does not offer 100% protection as the virus can still reach the eyes from exposed sides.^[9] Additionally, eyeglasses are regularly touched and adjusted throughout the day and comprise of materials that can harbor the virus. The viability on plastic has been demonstrated,^[3] and the viability on glass may occur for up to 5 days.^[7] For these reasons, it is important to consider the use of disinfectants and to only touch eyeglasses with clean hands.

Contact lenses
As a precaution, the American Academy of Ophthalmology has also recommended patients who wear contact lenses to switch to glasses during this time.^[9] The rationale is that this would decrease the frequency of contact lens wearers touching their eyes.

Credit cards
Credit cards are frequently used, and thus, contacted regularly. In addition, they consist of plastic materials, and so can potentially harbor the coronavirus for 72 hours.^[3] Thus, it may be important to consider disinfecting credit cards after use and engaging in proper handwashing. Also, when possible, one can minimize the contamination of credit cards by using online payment methods, or by utilizing the credit card chip inserter, rather than handing the card to another person.

Cash
Though there isn’t any evidence around the transmission of COVID-19 via paper currency and coins, a 2014 review suggests that the potential of viral transmission through money is possible.^[10] Further, a 2020 review suggests that coronaviruses may persist on paper for 4-5 days, and on metal for up to 5 days.^[7] Proper handwashing after making contact with cash or coins should be considered, along with avoiding contact with the face while handling these items.

Grocery bags and deliveries
Keeping in mind the viability of the virus on plastic, plastic grocery bags may also need to be handled with a level of caution by avoiding touching the eyes, nose, and mouth, and engaging in proper handwashing.

With regards to deliveries, specifically cardboard delivery boxes, no viable virus was found on cardboard after 24 hours of application to the surface.^[3] The virus can, however, be viable up to that time, and so, either waiting 24 hours prior to making contact with such surfaces or handwashing and avoiding contact with the face should be considered. One may also consider the half-life of the virus. For cardboard surfaces, the median half-life has been found to be slightly under 4 hours;^[3] waiting this amount prior to contacting this surface can minimize exposure to active viral particles.

Table 1 and Table 2 of this article summarize the viability and half-life of the virus and a comparison of biocidal agents.

Fur and pets
According to one study, cats can be infected with COVID-19 and may be able to pass it to other cats.^[11] The mode of transmission is not yet understood, and there is no current evidence of pets passing the virus to humans.^[12] This study also found ferrets to be highly susceptible to this infection, whereas dogs are less so.^[11] In addition, there are reports of a cat in Belgium being infected, and two dogs in Hong Kong.^[12]

As a precaution, the Centers for Disease Control and Prevention recommends that if a human is infected with COVID-19, contact with pets should be limited, including petting them, being licked, and sharing food.^[13] The CDC also recommends hand washing before and after making contact with pets, their food, waste, or supplies. ^[13]

Cell phones
Though there is no data around the viability of the COVID-19 virus on glass surfaces, other strains of the virus may survive on glass surfaces for up to 5 days.^[7] In addition, cellphone cases may be plastic of which the virus’s viability has also been demonstrated.^[3] Nevertheless, mobile phones are objects we make contact with on a daily basis, bring onto or close to our face, and carry with us when we leave the home. They can be a source of re-infection or re-exposure if not properly addressed; thus, it is important to practice proper hand hygiene and to consider the use of disinfectants, such as 70% alcohol wipes.

Keyboards
Computer keyboards are surfaces we also contact regularly, especially when many individuals are currently working from home. Considering the plastic material of keyboards, and thus, their ability to harbor the virus, it is again important to be mindful of hand hygiene, contact with the face, and the use of disinfectants. It is especially important to consider these precautions if computers are being shared with others.

Takeaways
• Some of the most important measures we can take at this time include proper hand washing, avoiding contact with the eyes, nose, and mouth, and physical distancing.
• Disinfectants with 0.1% sodium hypochlorite, 0.5% hydrogen peroxide or at least 62-71% ethanol are effective in reducing the infectivity of the coronavirus.
• The biocidal agent's benzalkonium and 0.02% chlorhexidine digluconate lack evidence for efficacy against the coronaviruses and should be avoided.
• The viability of the virus differs according to the surface material; plastic and stainless steel may harbor the virus for up to 72 hours, cardboard for 24 hours, and copper for 4 hours.