Surface safety to stop the spread of Covid-19

Burt Rodrigues, CEO of Biodx, shares insights into surface safety

The Education MEC for the Eastern Cape, Fundile Gade, recently ordered legal action against a company that supplied sanitisers to Makaula Senior Secondary School, where 204 pupils and staff tested positive for Covid-19. The company also supplied nine other schools in the district with a product that was found to be sub-standard, containing very low volumes of alcohol. The question is how many other products out there are similar to this?

Know what you’re getting

There’s really only one question here – how careful were you when the coronavirus first hit and how careful are you right now? How effective are the products you’re using and how long will they actually last on the surfaces they’re applied to? And how long should they remain on the applied surface before you wipe them off? This could be anywhere you’re likely to touch - from doorknobs and light switches to chairs, remote controls and table surfaces. And in the case of schools, even more areas are included.

In the early days of the pandemic, supermarket shelves were cleared of anything that said ‘cleaning or disinfection’ on the label, with people frantic to rid their homes and offices of anything viral. Strong smells emanated from rooms, especially kitchens, which had been doused with disinfecting products. But how effective were these products?

One thing is for certain: we now know more than we did about the virus and surfaces than at the beginning of this pandemic – although in terms of the virus' behaviour that’s not saying a lot.

How effective are the products you’re using and how long will they actually last on the surfaces they’re applied to?

At this point, unfortunately many places have sold out of authentic products. Those are products registered through the NRCS (national regulator for compulsory specifications) or the SABS (South African bureau of standards). Many of the products being sold now simply don’t come with this type of guarantee. What buyers and managers of companies and government departments must do is if the products they use have not been certified by these agencies, then at least the manufacturers must provide laboratory analysis demonstrating the product’s efficacy.

Terms you need to know

  • Decontaminate: Removal of pathogens from objects so they are safe to handle, use, or discard. It is an umbrella term for pre-cleaning followed by sanitising, sterilising or disinfecting.
  • Clean: Water, detergent (soap) and mechanical friction to reduce pathogen load, organic matter and dirt. Detergent does not kill pathogens.

  • Sanitise: Lowering the number of pathogens to a safe level by either cleaning or lower-level disinfection.
  • Disinfect: Type of decontamination using disinfectants to kill ~100% of pathogens. Easily deactivated by organic matter and dirt.
  • Sterilise: Type of decontamination using heat and steam often via autoclaving.

The routine cleaning and disinfection of surfaces is recommended for lowering the spread of Covid-19. 

Clean first (to reduce pathogen load, organic matter and dirt), then disinfect (to kill remaining pathogens). Routine cleaning of hands (with soap and water) and sanitisation (in the absence of soap and water). We know from various world scientific and health organisations that each surface has a different reaction to the virus in terms of how long it can live. 

If your local shop doesn’t have approved disinfectants, what should you use?

  • Use 70-90% ethanol (or other types of alcohol e.g. isopropyl alcohol
  • Use chlorine solution (sodium/calcium hypochlorite, such as bleach (Jik)
  • 0.1% (1000 ppm) for general environmental disinfection
  • 0.5% (5000 ppm) for blood and bodily fluid spills
  • Hydrogen peroxide at ≥ 0.5%
  • Contact time for above disinfectants: 1 minute. Contact time is the time for the disinfectant to be in contact with surface in order to kill pathogens
  • Type of disinfectant will be determined by type of surface to be cleaned (contact manufacturer if unsure)

Cleaning myths and harmful methods

“As this invasive virus doubles and triples in daily cases and deaths, there have been various commercial entities jumping on the bandwagon to introduce different ways to keep people and surfaces clean and disinfected. One of these has been the disinfection spray tunnels/booths which many schools/companies/mines have installed for people to pass through before entering their premises." Professor Salim Abdool Karim, chair of the ministerial advisory committee on Covid-19, says of these, “Human spraying is harmful with almost no benefit.”

“This is backed up by several world bodies. The US's CDC (Centers for Disease Control) says it doesn't recommend the use of sanitising tunnels. "There is no evidence they are effective in reducing the spread of Covid-19. Chemicals used in sanitising tunnels could cause skin, eye or respiratory irritation or damage."

“The WHO (World Health Organisation) comments that "spraying of individuals with disinfectants (such as in a tunnel, cabinet or chamber) is not recommended under any circumstances. This practice could be physically and psychologically harmful and would not reduce an infected person’s ability to spread the virus through droplets or contact. As they start speaking, coughing or sneezing they can still spread the virus."

Most disinfectants are approved based on their application to surfaces by wiping and not based on their application onto individuals by spraying. The department of health, WHO, CDC, and other bodies also don’t recommend fogging. They do recommend deep cleaning via wiping disinfectant on surfaces after thorough cleaning.