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Spray take note: disinfectant tunnels do more harm than good


Spray take note: disinfectant tunnels do more harm than good

Medics and scientists say the mist is not intended for humans and can in fact help the virus enter the body

Consumer journalist
A man walks through a booth that sprays disinfectant on commuters before boarding taxis in Pretoria.
CLOAKED IN MIST A man walks through a booth that sprays disinfectant on commuters before boarding taxis in Pretoria.
Image: Phill Magakoe/AFP

You erect a tunnel and get people to walk through its disinfectant mist, eyes open, arms up – what could go wrong?

A lot, say health professionals, from the World Health Organisation to Prof Salim Abdool Karim, chair of SA’s ministerial advisory committee on Covid-19.

But that hasn’t deterred companies marketing disinfectant tunnels to residential estates, supermarkets, schools, student residences, commuter hubs and workplaces, all claiming the disinfectant they use in theirs is perfectly safe.

The Allergy Association of SA (AASA) this week slammed the practice as a misdirection of resources.

“Disinfection tunnels are expensive; driven by false, profit-driven advertising,” the organisation said in a statement published in the SA Medical Journal.

“Human spraying can detract from investing in proven simple strategies such as good hand hygiene and proper mask-wearing ... and give users a false sense of security.”

Medics and scientists argue the “mist” is invariably intended for surfaces, not humans, has not been tested in a tunnel, and in any event is ineffective in curbing the spread of the coronavirus.

“There is no evidence that people, children or adults, who walk through fumigation tunnels have less incidence of Covid-19 or spread the virus less than people who do not use fumigation tunnels,” Abdool Karim told Times Select.

“This is essential information to determine whether body fumigation or spraying has any benefit in preventing Covid-19.”

There is no evidence that people who walk through fumigation tunnels have less incidence of Covid-19.

Showing that a disinfectant chemical kills the coronavirus in a test tube, surface or in animals was not evidence that it would prevent Covid-19 in humans, he said.

“Since the coronavirus does not enter through skin, there is no reason to spray the skin or clothes.

“And spraying chemicals on a person’s skin may alter the protective natural bacteria that are an important part of our protection against skin diseases and skin reactions,” he said.

“The virus enters through the mucosal surfaces of the mouth, eyes and nose. When fumigation/spraying does reach these sensitive parts of the face, it is often toxic and an irritant, causing damage to the lining of the mouth and throat that may increase susceptibility to the coronavirus.”

Wouter Conradie, MD at Africa Operations for NSF Africa, a global public health organisation, said he’d investigated the chemical used in one such tunnel erected at a residential estate in Somerset West, for visitors and domestic workers.

“It turned out to be chlorine dioxide, which is effective in killing the coronavirus, but only on hard surfaces,” he said.

“The MSDS [Material Safety Data Sheet] warns that one should avoid it coming into contact with skin, eyes and clothes.”

He advised concerned consumers to ask for disinfectant tunnel manufacturers or the establishments that have erected them for the MSDS for the disinfectant used. “In the Somerset West case, I was told that they product is registered by the EPA [Environmental Protection Agency] in the US.

“I took the reference on the letter and looked up the actual registration data on the EPA website, and that’s how I discovered the product being used contained chlorine dioxide, which is intended only for hard surfaces and will only be effective if left on the surface for several minutes to dry.

“It would most certainly not work on fabric. And it should not be allowed to come in contact with the skin and eyes or clothes.

“The residential estate immediately discontinued the use of the tunnel and informed the supplier, who responded by suggesting an organic biocide, which is registered for use in agriculture and only tested on three bacteria (E. coli, Salmonella species and Staphylococcus aureus).

“It was not tested on a virus, and certainly not on humans or on clothes.”

As a global public health organisation, NSF “strongly advises” against the use of fumigation tunnels, Conradie said.

“There is absolutely no proof that fumigation tunnels have any positive effect in combating Covid-19, but they are known to cause human health issues,” he said.

It was not tested on a virus, and certainly not on humans or on clothes.

When schools reopened this month, a private school on the KZN south coast erected a disinfectant tunnel at its entrance and instructed pupils to walk through it with their eyes open and their hands up, palms open.

Faced with objections from some parents, the school relented and made the tunnel walk voluntary.

“Those tunnels could most certainly not be enforced as a barrier to enter a place,” Conradie said. “People must have a right to refuse based on what our government, and the World Health Organisation (WHO) recommends.”

Knowles SuperSpar in Pinetown, KZN recently erected a disinfecting tunnel at the store entrance, assuring customers it was harmless.

The SPAR group has not responded to questions.

A store employee told Times Select it remained on site but was not operating.

The WHO has advised that the spraying of people with disinfectants in booths or chambers is “not recommended under any circumstances”, saying the practice could be harmful and would not reduce an infected person’s ability to spread the virus through droplets or contact.

The AASA said it was particularly concerned about the adverse effects on those with asthma, allergic rhinitis, allergic conjunctivitis and eczema.

“It is not effective in reducing the spread of the novel coronavirus as surface disinfection generally requires five to 10 minutes of contact with a surface to be effective, and the main body parts that transmit the virus – the respiratory tract and the hands – are not protected by surface spraying.

“When the person exits the tunnel, the respiratory tract remains infectious if they have the coronavirus, and the hands can rapidly become contaminated again with surface contact, so there is no extended benefit.”

Chemicals, “often of unknown quality and composition”, can result in significant eye and skin irritation, AASA said.

“Such chemicals are made for inanimate surfaces, not the human body.

“With inhalation, chemicals can irritate the respiratory system and cause bronchospasm and asthma attacks, and resultant coughing and respiratory tract damage can actually increase the spread of the virus.”


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