PRESS RELEASE: UK child trials block action for clean air schools.


Between August 2021 and September 2022, a Randomized Control Trial (RCT) went ahead in 30 primary schools in Bradford on the feasibility of using air cleaners to reduce the spread of airborne pathogens such as Covid-19.

Funded by the Department for Health and Social Care, the study investigated two approaches: HEPA filtration, which captures most airborne viruses, and ultraviolet germicidal light, which inactivates microorganisms, including viruses. 

Many concerned parents contacted us questioning the ethics of the study.

On 18 August 2021, SafeEdForAll wrote to the Department For Education (DfE), requesting the following details about the ventilation trials under the Freedom of Information act:

1. Please provide the RCT trial outline document. To be explicit so that there is no confusion regarding what I am asking for, I would like the FULL proposal with all details of: 

a) sample size

b) equipment to be trialled,

c) how the sample was selected, 

d) selection criteria of chosen trail equipment, ) details of who will be conducting assessments, 

f) what those assessments and evaluations are, 

g) details of how the proposed length of the trial was decided, 

h) details of WHO proposed an RCT was appropriate at this time 

i) rationale regarding the requirement for a trial (review of all

available studies must have led to a knowledge gap that these trials are seeking to answer and provide the detail of what is missing

from all other school setting studies of ventilation technology) 

2. A copy of the letter from the DfE sent to those schools that are

participating in the RCT trials. 

3. A copy of the ethics submission document 

4. A copy of the ethics approval document 

5. Details of the liability insurance which covers this RCT

On 15 October 2021, the DfE replied:

“Following a search of the Department’s paper and electronic records, I have established that the department does not hold the information you have requested. The information is held by the Department of Health and Social Care (DHSC). I would advise you contact DHSC directly at:”

On 27 October, Safe Ed received a response from the DHSC:

“DHSC does not hold the information you have requested. This is because we are not the appropriate authority to contact on this subject. However, you may wish to contact the Department for Education (DfE), which may hold information relevant to your request.”

If neither the DfE nor DHSC had the details about the Bradford Trials that went ahead in 30 schools, who authorised them without scrutinising these details?

SafeEdForAll Parent Advocate Sarah Saul said:

“I’m still shocked regarding the lack of transparency surrounding these so-called ‘ventilation trials’. Like the DfE’s other ‘trial,’ requiring household contacts to swap isolation for daily testing, no consent seems to have been sought from those impacted most heavily in the trials.

“No release of ethical approval documents, names and associations of all involved in the trial’s design, monitoring or reporting were made available. Most shocking of all, the FOI submitted by SafeEd received a response from the DfE that stated they did not have this information and that answers to information about the design and approval of the trials should be sought from the Department of Health.

“Why was there such a lack of transparency? How can it be possible for RCT to be conducted on our children, school staff and families without transparency and full detailed disclosure regarding design and ethics?”

Why did we need RCT when HEPA technology is known to work?

The technology was invented in the 1940s to prevent the spread of airborne radioactive contaminants in the Manhattan Project. It was commercialised in the 1950s and quickly became the gold standard for air quality across high technology industries, including hospitals, healthcare and the pharmaceutical industry. The NHS has been using HEPA technology to boost infection control for decades.

SafeEdForAll Parent Advocate Kim Wareham said:

“Parents have contacted SafeEd to voice their concerns about the poor air quality in schools because it negatively affects their children’s attendance. Some have said head teachers have turned down their donations of HEPA filter units. In many cases, local public health has informed school leaders that the local authority is waiting for the outcome of the Bradford RCT. 

During a school attendance crisis, it’s a travesty that UK schools have had to wait over a year to see if we can implement proven air cleaning measures. In contrast, countries like Germany have been promoting HEPA filtration in schools since 2020!”

The WHO states:

“Before your child is enrolled in a study, it’s important that you and your child understand the risks and benefits of participating. Because your child is a minor, you may be legally required to give informed consent allowing them to participate. Your child may also need to give their assent after having the trial explained to them in an age-appropriate manner. Both you and your child should have the chance to ask any questions you want before you agree to participate, and also at any time during the study.”

Contact and press enquiries:

Claire Cozler

Nicky Hutchinson


Twitter: @safeedforall_uk


1. WHO: Clinical Trials in children:

2. BRITANNICA: High-Efficiency Particulate Air System (HEPA)

History and Use:

3. The German government is investing €500m (£452m; $488m) in improving ventilation systems in public buildings:

4. Bradford Randomised Control Trials:

SafeEdForAll’s Initial Freedom of Information Request
The Department for Information’s Response
The Department for Health and Social Care’s Response


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