Shared agreement on the terminology was reached between WHO and experts from the Centers for Disease Control and Prevention in Africa, China, Europe and the United States. Under the umbrella of “airborne transmission,” two descriptors may be used: airborne transmission or inhalation, for cases where infectious respiratory particles are expelled into the air and inhaled by another person; direct deposition, for cases in which infected particles are deposited directly onto the mouth, nose or eyes of another nearby person. THE REPORT
19 APR –
Following consultation with public health agencies and experts, the World Health Organization (WHO) has published a global technical consultation report introducing updated terminology for airborne pathogens. Pathogens covered include those that cause respiratory infections, such as Covid-19, influenza, measles, Middle East respiratory syndrome (Mers), severe acute respiratory syndrome (Sars), and tuberculosis, among others.
The publication, entitled “Global Technical Consultation Report on Proposed Terminology for Airborne Pathogens”, is the result of an extensive multi-year collaborative effort and reflects shared agreement on terminology between WHO, experts and four major public health agencies: Africa Centers for Disease Control and Prevention; China Center for Disease Control and Prevention; European Center for Disease Prevention and Control; and U.S. Centers for Disease Control and Prevention. This agreement highlights the collective commitment of public health agencies to move forward together on this issue.
The extensive consultation was conducted in multiple phases in 2021-2023 and addressed the lack of common terminology to describe airborne pathogen transmission between scientific disciplines. The challenge has become particularly evident during the Covid-19 pandemic as experts from various fields have been asked to provide scientific and policy guidance. The different terminologies have highlighted gaps in common understanding and contributed to challenges in public communication and efforts to curb transmission of the pathogen.
“Together with a very diverse range of leading public health agencies and experts across multiple disciplines, we are pleased to have been able to address this complex and timely issue and reach a consensus,” he said. Jeremy Farrar, chief scientist of the WHO -. The agreed terminology for airborne pathogens will help establish a new path for research programs and the implementation of public health interventions to identify, communicate and respond to existing and new pathogens.”
Extensive consultation has led to the introduction of the following common descriptors to characterize the transmission of pathogens through the air (under typical circumstances):
– Individuals infected with a respiratory pathogen can generate and expel infectious particles containing the pathogen through the mouth or nose by breathing, speaking, singing, spitting, coughing, or sneezing. These particles should be described by the term “infectious respiratory particles” or IRP.
– IRPs exist on a continuous spectrum of sizes and no single cut-off point should be applied to distinguish smaller particles from larger ones. This facilitates abandoning the dichotomy of previously used terms: “aerosol” (generally smaller particles) and “droplets” (generally larger particles).
The descriptor “through the air” can be used in a general way to characterize an infectious disease in which the primary mode of transmission involves the pathogen traveling through the air or being suspended in the air. Under the umbrella of “air broadcast”, two descriptors can be used:
1. Airborne transmission or inhalation, where IRPs are expelled into the air and inhaled by another person. Airborne transmission or inhalation can occur at a short or long distance from the infected person, and the distance depends on various factors (air flow, humidity, temperature, ventilation, etc.). IRPs can theoretically enter the body at any point along the human respiratory tract, but preferred entry sites may be pathogen-specific.
2. Direct deposition, for cases where IRPs are expelled into the air by an infected person and are then deposited directly onto the exposed mouth, nose, or eyes of another nearby person, thus entering the human respiratory system and potentially causing infection .
“This global technical consultation process has been a concerted effort by many influential and experienced experts,” he said Gagandeep Kang, Christian Medical College, Vellore, India, Co-Chair of the WHO Technical Working Group. “Reaching consensus on these terminologies by bringing stakeholders together in an unprecedented way was no mean feat. The completion of this consultation provides us with a new opportunity and starting point to move forward towards better understanding and agreed principles for diseases that are transmitted through the air,” added YGuo Li from the University of Hong Kong, Hong Kong SAR (China), who also co-chaired the technical working group.
This consultation was the first phase of global scientific discussions led by WHO. Next steps include further technical and multidisciplinary research and exploration of the broader implementation implications of the updated descriptors.
April 19, 2024
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