“Deep cleaning does not make a lot of sense,” explains Jack Gilbert, professor of paediatrics at the University of California, San Diego, and a specialist in microbes and the immune system. “It is stage craft - security theatre.”
The above is a response to a question on the latest Tes Podagogy podcast about whether transmission of the coronavirus can be curtailed in schools by liberal use of bleach. He’s not convinced that the impact would be substantial, for the simple reason that our best evidence suggests that most children won’t get the virus from touching a surface.
You can listen to Professor Gilbert on the Tes Podagogy podcast here
“Whenever we talk about advice, we need to understand that this is an emerging field, all the research is in its infancy and open to revision as we get more evidence, but in the context of that - the [evidence we have suggests the] vast majority of transmission of coronavirus is airborne,” he explains.
“Your biggest risk is breathing in contaminated air. If someone had a lot of virus on their hands, and they touched a door handle, and then someone came along and touched that door handle then touched their nose or eyes or mouth, then it is possible they will become infected. But we have not found a lot of evidence of those forms of transmission.
Coronavirus: What schools can do to protect staff and pupils
“People get sick from interacting with each other and breathing in each other’s contaminated air. So you can clean all you want, but if an infected person comes into that school then they are likely to spread it through interaction, not through surfaces.
“But I am not going to tell people to stop doing it - we are being doubly safe, it is belt and braces.”
You can also watch the podcast here:
Gilbert’s work involves studying microbes and their impact on children, which includes extensive research on the immune system. He says that the health risks of staying indoors need to be weighed against the benefits of minimising coronavirus transmission risks by keeping pupils in one classroom and reducing break times.
“Being trapped inside concentrates viruses and bacteria, from the people who are in there, in the air and on surfaces ,” he says. “In a pandemic, that is why you are told to wear a mask and try and be outside.
“[But there are other health risks, including] chemicals off-gassing from the furniture and the technology and the materials of the building - they can build up in the air and if there is not proper ventilation then those can build up and they can have negative effects.
“Particularly in old buildings, there may also be fungi moulds living in the building structure producing volatile organic compounds, and they can get into the air and make us sick.
“So there are lots of complications biologically in keeping people inside in the same space. Making sure people get enough exposure to the outside, and that the inside is properly ventilated, is going to be the really difficult task of kids being back into schools during the pandemic.”
As well as the issues around the coronavirus, the podcast tackles general issues around health and schools, including how the immune system is primed in the first 18 months of life and how continual exposure to other microbes is beneficial.
“If your immune system does not see lots of things, it can become lazy - and a lazy immune system can overreact when it finally starts to see antigens,” explains Gilbert. “So what we have found is that if your immune system sees a lot of things early in life, within the first 18 months, it can be trained so it does not overreact when it finally sees something it is not expecting.”
Developing the immune system
That’s not to say the immune system is then set for life: our best guess is that continual exposure to foreign microbes is essential. Gilbert explains that each of us has a microbial aura around us, and if we sneeze we project that aura further afield. Also, if we are close to someone else, they will breathe in our aura and we will breathe in theirs.
“This is usually beneficial,” he says. “With two healthy children sitting next to each other, their immune systems are being educated by the other person’s microbial exposure - so the bacteria and viruses and other microbes that child is emitting - and remember we each emit 38 million microbial particles per hour.”
What about the teachers? Usually, healthy interaction with others is a benefit to teachers for the same reasons as it is for students. But why then do teachers always get sick in the holidays?
“We see a similar thing with people who work in sewage treatment plants,” says Gilbert. “They get low rates of infectious disease during work, but when they take a break or retire they got a lot sicker.
“We think that the constant exposure to things keeps the immune system very alert, and when it is very alert it is constantly refreshing immune cells. When it is not on high alert, those immune cells hang around longer and they get older and they become more reactive. This means viruses can be more likely to infect you as the immune system is less reactive, and then when it suddenly responds it reacts very strongly. That makes you more severely ill.”
Impact on learning
The podcast covers many more areas, including to what extent outside learning is beneficial, why diet is so crucial to the immune system, how the immune system impacts on learning and a very interesting discussion about toilets.
“The vast majority of the microbes you are exposed to in a [school] toilet are not harmful - I mean, I wouldn’t lick a urinal, but just being in there might actually be beneficial to training your immune system,” says Gilbert. “As long as there is not a pandemic going on, of course. Generally, there is virtually nothing in most people’s faeces that will make you ill.”
Listen on the player above, or search for ‘Tes Podagogy’ on your podcast platform
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