A new report confirms what Karolinska University Hospital suspected early on. COVID-19 is largely spread through the air and poor ventilation increases the risk of infection. At the start of the pandemic, Karolinska immediately invested in mobile air cleaners to reduce infection in vulnerable environments, where COVID-19 patients were treated during the pandemic.
When the first wave of the pandemic struck during spring 2020, Karolinska University Hospital opened several larger intensive care units in Solna and Huddinge to care for COVID-19 patients. Work environment specialist Peter Ryd was part of the group tasked with procuring protective equipment and securing the working environment on the wards.
– “In the early days, COVID-19 was classed as an infection spread only by droplets and direct contact. However, we suspected that the infection might be airborne, especially among patients receiving high-flow therapy. This is why we took steps to ensure improved air quality,” Peter Ryd says.
Early on, Karolinska decided early on to buy mobile air cleaners for the care units where negative pressure could not be created using ventilation alone, and where COVID-19 patients received high-flow therapy. Throughout the pandemic, more than 200 air cleaners were installed at the two Karolinska hospitals, with the majority at Huddinge, as it has an older ventilation system.
– “Our measurements show that we succeeded in creating almost particle-free areas,” Peter Ryd says. At the hospital, sickness absenteeism among staff remained high during the pandemic, but the staff who worked the closest to COVID-19 patients were among those who had the best protection. This was partly due to their personal protective equipment and partly because mobile air cleaners were used.
The air cleaners are equipped with HEPA 14 filters and clean the indoor air five to six times per hour, compared to the regular ventilation system which replaces the air in the room about two times per hour. Each air cycle that passes through the HEPA 14 filter reduces particle levels by 99.995%. This includes virus particles, bacteria or other particles. A new report on respiratory viruses published by the University of Gothenburg shows that the coronavirus is largely airborne, and that poor ventilation increases the risk of infection.
– “The report gives us confirmation that we acted correctly during the pandemic in our efforts to combat airborne infection” Peter Ryd continues. “Air cleaners, coupled with primary protective aids, good hygiene practices and personal protective equipment, have given healthcare staff an extra source of protection in their working environment”.
During periods with a reduced need for COVID-19 wards, the air cleaners have been used to reduce airborne particles in i.a. waiting rooms, staff rooms and medicine storage rooms. Now, Peter Ryd works with one of the hospital’s chief physicians, an expert on air cleaning in operating rooms and an infectious disease physician to prepare a set of guidelines with recommended uses for air cleaning in healthcare.
– “Karolinska was quick to use mobile air cleaners and the strategy has been very successful. We now want to share our experiences with others,” Peter Ryd concludes.
Karolinska University Hospital breaks new ground in protecting staff from the coronavirus
Report: Respiratory virus at workplaces – Routes of infection, risk factors and protective measures (in Swedish)
Article by Karolinska University Hospital – First in the country with air cleaners to secure the work environment (in Swedish)
Article on Sunt Arbetsliv (Healthy Work life ) – Corona: How employers can reduce the risk (in Swedish)