We now know that air cleaning with portable HEPA filtration can inhibit the transmission of SARS-CoV-2, the virus which causes COVID-19.
Thanks to confirmation that the hotly anticipated Classroom air cleaning technology study (AKA Class-ACT - who said scientists don’t have a sense of humour?) met its end point of reducing absences, we can now be sure of the following:
The absence of a study of this kind into the effect of air cleaning has been regarded as a significant gap by some in the scientific community. We need scientific consensus so it’s good news that this has been addressed.
And while we don’t yet have full peer reviewed details of the outcomes, schools randomised to the HEPA arm of the study are reported to have had “illness rates over 20% lower than those in the non-HEPA arm” according to Professor Cath Noakes, the study’s lead investigator who disclosed this figure at the WHO/ Europe conference on indoor air on September 20.
These results are especially encouraging as study set up was in Bradford from early 2021 and the trial period encompassed waves of Delta and Omicron. At this time relatively few people had any immunity to SARS-CoV-2 from past exposure or vaccination (more on this later).
Initially the study tested 2 types of technology:
The ur-UVGI arm of the study was cancelled however, leaving only the HEPA arm.
HEPA filtration physically removes suspended virus laden aerosols from the air with incredible efficiency. A unit can clean far more air far faster than you and several of your friends can possibly breathe it in, so by the time it gets into your airways the amount of virus in it is much reduced. See here for more information.
The effect of this is to reduce your exposure to live virus and reduce risk of infection. And reducing exposure is important (read on for why).
Most of us have now had COVID-19, many of us several times. Additionally in many countries a majority of the adult population have been vaccinated (sadly the story is different for children, but more on this in a moment).
A study published recently in Nature showed convincingly that immunity to COVID-19 acquired either through vaccination, infection or both (so called hybrid immunity) is very protective against future infection even by new variants as long as exposure to the virus is low to moderate and not high[1]. This form of immunity is known as “leaky immunity” - immunity which leaks.
This level of population immunity has been hard earned. Millions have died on the road to it, millions more have been disabled by LongCovid. Deaths due to COVID-19 and cases of LongCovid still occur every day.
But immunity isn’t perfect. It is leaky.
In order to reduce the number of times we, and our children, catch COVID-19, we must avoid high exposure to the virus, which we can do by cleaning the air.
The Class-ACT study finally gives us concrete, real world evidence of how we can achieve this universally, cost effectively and without changes to our way of life. These are unobtrusive technological solutions that don’t harm or disrupt daily life in the slightest.
The results of this study are simply too powerful to ignore.
It is also highly relevant that this study was conducted in schools. It is undisputed that children have had their education disrupted in this pandemic, and widely recognised that children remain undervaccinated. They have been denied a voice while frequently unevidenced assertions about their wellbeing have been used to push positions which are ideological rather than moral or evidence based.
COVID-19 is harmful to children and it is clear we should protect them from it. Prevention is a priority.
A recent study showed that in the US COVID-19 was the leading cause of death from infectious disease among under 18s[2]. In the UK to date 186 children have died of COVID-19, 38,079 children have been hospitalised due to infection and it is estimated that over 69,000 children currently live with debilitating symptoms of Long Covid, around 53,000 of whom have suffered symptoms for more than one year[3].
Children are undervaccinated (in the UK vaccination is not even offered to them) and we have no idea what the long term implications of childhood COVID-19 are. Emerging evidence relating to diabetes[4] as well as excess mortality across all age groups[5] means we can’t discount the possibility of serious outcomes.
On top of this schools absence in the UK is at record levels[6], and while the causes of this are multifactorial there can be little doubt that increased illness plays a role.
We must protect our children from COVID-19.
This means reducing their exposure to the virus which causes it so that their immunity can exert its maximal effect.
We must clean the air that our children breathe in schools.
We clean our water and treat our sewage, we disinfect surfaces, we can practise safe sex and we can erect barriers to vectors like mosquitos. The one thing we do not do at this moment in time is clean the air we breathe.
Airborne disease transmission is a huge, unaddressed vulnerability.
Bluntly, if we want to reduce the risk of disrupting education, or, for that matter, the business of enterprise, offices, care homes or hospitals in response to disease outbreaks and if we want to ensure the health, longevity and wellbeing of our children we must clean indoor air.
And if you think COVID-19 has gone away or isn’t now a problem, air cleaning isn’t just about COVID-19. A wise man once said to us that only 4 things are certain in life; Death, Taxes, Flu Season and Future Pandemics.
It’s time to stop arguing. It’s time to act.
We know that clean air saves lives. Let’s clean our indoor air.
