Chemical spray booths are dangerous, experts now warn


What you need to know:

  • The agency argues that the chemicals are only effective when they follow a thorough cleaning protocol.
  • According to the Africa CDC, disinfection spraying of the environment is not effective.
  • This is because many of these do not work in the presence of organic matter such as soil or grass.

The use of chemical spay booths is dangerous to people’s health, the Africa Centres for Disease Control and Prevention (Africa CDC) and the Infection Control African Network (ICAN) has warned, adding that this move a waste of public resources.

This comes even as experts warn that handwashing, sanitising, disinfection of houses, countertops, office desks and tabletops coupled with stay-at-home orders to wade off the coronavirus infection could have detrimental effects on our immunity.

Tunnels, booths or double-gated structures have all been used to disinfect people using chemicals with more counties including Nyandarua joining Mombasa which debuted with the spray sanitisers at the Likoni ferry crossing.

During the launch, Mombasa Governor Hassan Joho tapped in experts from the county’s public health department and the Technical University of Mombasa (TUM) to ensure that the reagents used are safe, more so for those with repository problems and allergies.


Dr Josiah Odalo, a professor of chemistry at TUM, said that the disinfectant is anti-microbial and it well help to control the spread of the coronavirus.

“The kind of reagent you are going to disinfect yourself with is safe. We have prepared it using locally available resources from our laboratories which is under good quality assurance mechanism. This formulation is quite safe and it meets WHO standards,” he said then.

But now, Africa CDC says that the direct spraying of humans with chemical disinfectant or exposing them to ultraviolet (UV-C) light is not recommended, given that these chemical disinfectants are designed for use on hard surfaces, not the human body.

“These chemicals can irritate the skin, mucosa (e.g. eyes, nose and mouth) and the respiratory tract. Additionally, they can irritate the digestive tract, cause cancer, and can generate air pollution in the form of ozone. The doses and contact times needed for chemical or UV-C disinfectant to work are not feasible in a tunnel or with a sprayer, without causing considerable harm to humans, and may aggravate the transmission because of damage to the respiratory tract,” the African Union CDC said.


The agency argues that the chemicals for disinfection have only been tested on surfaces, and are only effective when they follow a thorough cleaning protocol.

“There is no evidence that use of disinfection tunnels or spraying of humans reduces transmission of any infectious disease including SARS CoV2. Spraying humans with disinfectants does not treat the virus inside the body,” the agencies say, adding that the high pressure spraying of surfaces contaminated with Covid-19 may actually disperse the virus causing further spread.

According to the Africa CDC, disinfection spraying of the environment is not effective because many of these do not work in the presence of organic matter such as soil or grass – they do not act on porous surfaces like pavements and roads, and they have a detrimental impact on the environment.


On the dangers of ‘over-sanitisation’, experts argue that while staying at home is not expected to directly affect the immune system, factors such as stress, depression, or bad health habits, may affect it.

Dr Geoffrey Kulabusia, a medical immunologist, agrees that a number of infectious diseases like gastrointestinal infections, such as Salmonella and respiratory infections such as influenza can be spread from one person to another by contaminated hands and, therefore, proper handwashing can help prevent the spread of the germs (like bacteria and viruses) that cause these diseases.

To contain Covid-19, the World Health Organisation (WHO) issued a directive for people to wash their hands for at least 20 seconds with soap and water or sanitise. But physicians and immunologists are reconsidering the antiseptic, at times hysterical, ways in which people interact with the environment as this interaction also helps prevent some allergic diseases.


The recommendation is informed by the fact that it is not yet clear how long the virus can remain or live on the skin. That is why it is important for people to wash hands and avoid touching their faces whenever they touch an object that others may encounter.

Although he supports the handwashing advice, Dr Kulabusia argues that many of the sanitisers and soaps being used are harsh to the skin, making it more prone to infections.

“There are patients with contact dermatitis who cannot wash their hands frequently. Further, some of the products in the market do not adhere to the requirement needed to ensure that the soaps and sanitisers are safe for use,” Dr Kulabusia said.


Naturally, the skin produces protective microorganisms that help build a defence mechanism against infections.

However, with repeated handwashing, the immunologist who practices at Egerton University notes, these microorganisms are eroded, making the skin vulnerable to infections.

“The integrity of the skin determines the level of defences a person has. Our hands have a certain PH level and bacteria that lives on everyone's skin. When you exceed the recommended 20 seconds, and you are using antiseptic soaps, you risk eroding these bacteria,” explained Dr Kulabusia.


Staying at home also has its fair share of negative impacts.

In fact, Dr Kulabusia says that there is an increased secretion of some stress hormones known as Cortisol, especially among people who have lost their jobs.

“This hormone suppresses the body’s production of lymphocyte, which protects us from viral and bacterial infections,” he noted.

Lymphocyte is a type of white blood cell (leukocyte) that is of fundamental importance in the immune system because lymphocytes are the cells that determine the specificity of the immune response to infectious microorganisms and other foreign substances. In human adults’ lymphocytes make up roughly 20 to 40 per cent of the total number of white blood cells.

As Covid-19 infections continue to surge, different experts have varied opinions on how Kenyans’ immunity will look like, once normalcy resumes.

“I would tell you that the sanitising being done and the ‘staying at home’ I have seen in Kenya will not have any negative consequences on immunity. If people are eating well, exercising, sleeping well, there may even be positive effects on enhanced sanitation. The risk of other infectious diseases will probably reduce due to these sanitation measures,” Dr Lukoye Atwoli, an associate professor of psychiatry at Moi University’s School of Medicine argues.