From the Guidelines
COVID-19 can spread through airborne transmission, and to reduce this risk, it is essential to wear well-fitting masks, ensure good ventilation, maintain physical distance, and limit time spent in poorly ventilated indoor spaces. The SARS-CoV-2 virus can be transmitted through tiny respiratory droplets and aerosol particles that remain suspended in the air for minutes to hours 1.
Key Recommendations
- Wear well-fitting masks (preferably N95, KN95, or surgical masks) in crowded indoor settings to reduce airborne transmission risk 1
- Ensure good ventilation by opening windows or using HEPA air purifiers to minimize the concentration of airborne particles 1
- Maintain physical distance of at least 6 feet from others when possible to reduce the chance of transmission through respiratory droplets 1
- Limit time spent in poorly ventilated indoor spaces, as this can increase the risk of airborne transmission 1
Importance of Vaccination
Vaccination remains crucial for reducing transmission and severity of infection, and it is essential to follow recommended vaccination guidelines to protect against COVID-19 1.
Airborne Transmission
Airborne transmission occurs because the SARS-CoV-2 virus is contained in respiratory particles of various sizes expelled when an infected person breathes, talks, coughs, or sneezes 1. The smallest particles (aerosols) can travel farther than 6 feet and linger in the air, especially in enclosed spaces with poor ventilation, which explains why COVID-19 can spread in settings where people are physically distanced but sharing the same air for extended periods 1.
Personal Protective Equipment
The use of personal protective equipment, including masks, goggles, and gowns, should be carefully considered, especially in healthcare settings where the risk of transmission is higher 1. High-filtration masks, including N95, should be worn by healthcare professionals working in direct contact with infected patients 1.
From the Research
Airborne Transmission of COVID-19
- The airborne transmission of COVID-19 is a significant concern, and various studies have investigated the effectiveness of face masks in preventing the spread of the virus 2, 3, 4.
- A study published in MMWR found that always using a face mask or respirator in indoor public settings was associated with lower adjusted odds of a positive test result compared with never wearing a face mask or respirator in these settings 2.
- Another study published in mSphere found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2, although medical masks were not able to completely block the transmission of virus droplets/aerosols even when completely sealed 3.
- A systematic review and meta-analysis published in the European Journal of Medical Research found that face mask use was associated with a significant reduction in infection, with a pooled risk ratio of 0.12 [0.06,0.27] (P < 0.001) 4.
Role of Face Masks in Preventing Airborne Transmission
- Face masks are an effective way to prevent the airborne transmission of COVID-19, with N95 masks offering the highest level of personal protection against acquiring infection 2, 3.
- A study published in the Proceedings of the National Academy of Sciences found that the use of face masks, along with ventilation and air filtration, can help to reduce the cumulative exposure time and prevent the airborne transmission of COVID-19 5.
- The effectiveness of face masks in preventing airborne transmission is also dependent on factors such as the type of mask, the fit of the mask, and the respiratory activity of the wearer 3, 5.
Other Factors Influencing Airborne Transmission
- Ventilation and air filtration are also important factors in preventing the airborne transmission of COVID-19, with increased ventilation and air filtration rates helping to reduce the cumulative exposure time 5.
- The size and dimensions of the room, as well as the number of occupants and their respiratory activity, can also influence the airborne transmission of COVID-19 5.
- The infectiousness of the respiratory aerosols and the presence of respiratory jets can also play a role in the airborne transmission of COVID-19 5.