9 July 2020, Brussels.

REHVA welcomes the fact that the World Health Organization acknowledged in a press conference the emerging evidence of airborne spread of COVID-19 following an open letter by 239 scientists, including many REHVA experts, from 32 countries, published this week in the Journal Clinical Infectious Diseases. This step was long-awaited by REHVA and several professional organisation and scientific bodies across the world that have been advocating for considering the transmission via aerosols/micro droplets as possibility and apply necessary mitigation measures.
 

On 7 July, WHO acknowledged the possibility of airborne transmission evidence in specific conditions, especially in crowded, closed, poorly ventilated settings. “We believe we have to be open to this evidence and understand its implications regarding the modes of transmission and the precautions which need to be taken,” said prof. Benedetta Allegranzi, technical lead on infection control, adding that “the evidence is not definitive.” Dr Maria Van Kerkhove, technical lead on COVID-19 pandemic mentioned, that WHO is working on a consolidating brief, “we have spoken about the importance of all the different potential ways of transmission.”
 

“WHO has changed its position on the airborne transmission of COVID-19 based on a reliable teamwork of specialists from our member associations in the EU and around the world. Our COVID-19 guidance has considered this possibility relevant from the first release and our expert team proposed necessary measures on the safe operation of HVAC systems. We shared this work with members of the IEQ Global Alliance and we will continue to help building professionals and facility managers through the empowerment of our national members.” said REHVA President, Frank Hovorka.
 

Dr. Atze Boerstra, REHVA board member added, “I appreciate the excellent work that WHO has done the last couple of months fighting the corona virus. It is unfortunate that till now the role of aerosols in poorly ventilated rooms was underestimated. Changing the course will save many lives in the future. Recently, we worked with WHO to upgrade their ventilation guidance for hospital rooms. I hope that we can soon work with them to further define what the world can do to limit covid-19 transmission via air also in workplaces and other common non-hospital buildings.”
 

“This evidence will demystify infections of this virus, showing a clear mechanism why most of superspreading events have happened. Now we know that infection risk depends on aerosol concentration and occupancy time, the first one being a function of outdoor air ventilation rate and room size. The infection risk can be calculated for typical room layouts and preventive measures can be taken to improve ventilation in buildings. Until the medicine and vaccine are not available, ventilation solutions remain the most important infection control measures. If properly implemented, much less lockdowns would be needed in the second wave” concluded REHVA Technology and Research committee chair Profession Jarek Kurnitski.
 

This good news comes in the wake of many recent REHVA initiatives related to the COVID-19 pandemic. REHVA has published its guidance considering airborne transmission already in March 2020 and our experts are currently working on the second version. REHVA published two specific documents on fan coils with air recirculation, and on inspection of leaks in rotary heat recovery equipment last week. The third version of the guidance with further documents on school buildings and an infection risk calculator will follow in the coming weeks. In September, REHVA will launch an online course focusing on the safe and healthy operation of buildings after the lockdown and during the pandemic. This course will be especially relevant considering the arriving winter season when the infection risk will increase as people stay indoors with limited window airing. We need to prepare for the challenge of providing healthy indoor climate while being energy efficient in the winter.
 

Follow our COVID19-guidance page and social media for further updates.