Research published this week showed official Social Distancing guidelines given by WHO and the CDC are based on outdated information on coughs and sneezes. Novel coronavirus / COVID-19 guidelines from the World Health Organization (WHO) and the USA Center for Disease Control (CDC) suggests that peoople around the world should stay approximately 6 feet apart. Unfortunately, according to MIT associate professor Lydia Bourouiba, “pathogen-bearing droplets of all sizes can travel 23 to 27 feet.”
In the study published here in late March, 2020, Dr. Bourouiba showed that current guidelines for Social Distancing is based on models published in the 1930s. The video below shows a slow-motion sneeze, filmed for a study on the physics of sneezes and coughs by Dr. Bourouiba.
[The video shown above is courtesy of Dr. Lydia Bourouiba, posted by JAMA Network.] The video shows a close-up view of a sneeze filmed at 2000 frames per second. Dr. Bourouiba’s research shows “a hot, moist, turbulent gas cloud containing air and mucosalivary droplets that travel as far as 26 feet (7-8 meters).”
The World Health Organization recommendations for COVID-19, health care workers should stay at least 3 feet (approximately 1 meter) away from a person showing symptoms of disease, while the CDC recommends as 6-foot (2 meter) separation.
“However,” said Dr. Bourouiba, “these distances are based on estimates of range that have not considered the possible presence of a high-momentum cloud carrying the droplets long distances.”
“Given the turbulent puff cloud dynamic model, recommendations for separations of 3 to 6 feet (1-2 m) may underestimate the distance, timescale, and persistence over which the cloud and its pathogenic payload travel, thus generating an underappreciated potential exposure range for a health care worker.”
For more information on the study mentioned above, see: Bourouiba L. Turbulent Gas Clouds and Respiratory Pathogen Emissions: Potential Implications for Reducing Transmission of COVID-19. JAMA. Published online March 26, 2020. doi:10.1001/jama.2020.4756 – retrieved at JAMA Network on March 31, 2020.