We’ve collected a lot of evidence showing that the Covid virus can be transmitted through the air in tiny droplets. And that applies to hospital wards as much as anywhere else, as most don’t have the tech to change the air enough.
Given we’ve known about airborne transmission of Covid for so long and we’ve been obsessive about hygiene measures to control it, then why on earth have we not focused on air purifying sooner?
But researchers have been looking for ways to get cleaner air into Covid wards and intensive care units to reduce the risk of airborne transmission of infections.
When a team of doctors, scientists and engineers at Addenbrooke’s Hospital and the University of Cambridge placed an air filtration machine in Covid-19 wards, they found that it removed almost all traces of airborne Covid. Job done?
Not quite. The researchers wanted to investigate whether portable air filtration/UV sterilisation devices could reduce airborne Covid in general wards not designed to handle Covid patients but which had been repurposed as a Covid ward, and a Covid Intensive Care Unit (ICU).
Dr Vilas Navapurkar, a Cambridge Consultant in Intensive Care Medicine, who led the study, said: “We were able to pull together a team from across the hospital and university to test whether portable air filtration devices, which are relatively inexpensive, might remove airborne SARS-CoV-2 and make these wards safer.”
The team installed a High Efficiency Particulate Air air filter/UV steriliser in fixed positions that operated continuously for seven days, filtering the full volume of air in each room between five and 10 times every hour.
Once the air filter was switched on and run continuously, the team were unable to detect Covid on any of the five testing days. They then switched off the machine and repeated the sampling, and detected Covid on three of the five sampling days.
The air filters significantly reduced levels of bacterial, fungal and other viral aerosols on the ward and ICU, highlighting an added benefit of the system.
Author Dr Andrew Conway Morris, from the Department of Medicine at the University of Cambridge, said: “We were really surprised by quite how effective air filters were at removing airborne SARS-CoV-2 on the wards.”
Dr Navapurkar added: “We’re all familiar with the idea of having standards for clean water and of hygiene standards for food.
“We need now to agree standards for what is acceptable air quality and how we can meet and monitor those standards.”