WHO Report Concludes Respiratory Infections Spread Through Airborne Transmission

The World Health Organization (WHO) has released a report that challenges traditional beliefs about the transmission of respiratory infections like COVID-19, influenza, and measles. The report concludes that these diseases primarily spread through airborne transmission, where infected individuals exhale pathogens that remain suspended in the air and are inhaled by others. This finding emphasizes the critical need for improved ventilation and high-quality face masks to prevent the spread of these infectious diseases.

The WHO report signifies a notable change from the previous dogma that respiratory infections mainly spread through large droplets. By revising the terminology and explanations regarding the spread of SARS-CoV-2, the virus responsible for COVID-19, the WHO aims to provide a more accurate understanding of disease transmission. The report comes at a time when the world continues to confront the ongoing COVID-19 pandemic and a resurgence of measles cases in some regions.

Why this matters: The WHO report has far-reaching implications for public health measures and infection control practices. Recognizing the dominance of airborne transmission for many respiratory infections will guide the development of more effective strategies to mitigate the spread of these diseases, potentially saving countless lives and reducing the burden on healthcare systems worldwide.

While the WHO report provides valuable insights, it stops short of prescribing specific actions for governments, hospitals, and the public. The Centers for Disease Control and Prevention (CDC) is expected to update its guidance on infection control in healthcare settings based on this new information. However, a committee advising the CDC has drafted guidance that still maintains the traditional categories of short-distance and long-distance transmission, which some researchers and healthcare workers have criticized as being outdated and endangering public health.

The WHO's updated definition of airborne transmission expands the list of pathogens that can be spread through the air, including measles, the common cold, and the flu. This definition moves away from the previous focus on droplet size and instead describes two modes of spread: when a pathogen enters the human body through the respiratory system and is transmitted from another person's respiratory system. While some experts may argue for a more complex definition, the simple definition of transmission from one nose or mouth to another through the air is difficult to dispute.

Recent research has also shed light on the potential impact of increased carbon dioxide (CO2) levels on the survival of airborne viruses. A study by researchers at the University of Bristol found that higher CO2 concentrations in the atmosphere and indoor spaces can prolong the life of COVID variants present in tiny airborne droplets. The findings suggest that opening windows and reducing CO2 levels can help inactivate viruses faster, and that climate change goals to limit atmospheric CO2 could also help curb the spread of airborne viruses.

In response to the WHO report, the World Health Network (WHN) has emphasized the importance of recognizing the dominance of near-field and far-field aerosol spread for many respiratory infections. The WHN encourages the CDC to take an authoritative, scientifically and clinically assertive stance in its recommendations and use straightforward, up-to-date language on airborne aerosol transmission. The response also highlights the need for an integrated respiratory infectious disease strategy based on well-established scientific insights and evidence.

As the world continues to navigate the challenges posed by respiratory infections, the WHO report

Key Takeaways

• WHO report concludes respiratory diseases spread primarily through airborne transmission.
• Improved ventilation and high-quality masks are critical to prevent disease spread.
• WHO revises terminology on SARS-CoV-2 transmission, moving away from droplet focus.
• Higher CO2 levels can prolong survival of airborne viruses, suggesting need for ventilation.
• WHO report prompts calls for CDC to update guidance on airborne disease transmission.