Once again the country is on high-alert as a third-wave of COVID-19 transmissions emerges.
The novel coronavirus that causes COVID-19 (SARS-CoV-2) is most reliably spread via exposure to infected mouth and nose secretions (saliva, respiratory droplets).
We’re conditioned to primarily associate these transmission routes with coughing and sneezing but SARS-CoV-2 expresses an atypical modus and a significant portion of infected carriers will not display symptoms characteristic of respiratory illness.
Both of these factors elevate contraction means that would otherwise be overlooked.
“Medical reports and news sources raise the possibility that flows created during breathing, speaking, laughing, singing, or exercise could be the means by which asymptomatic individuals contribute to spread of the SARS-CoV-2 virus,” the authors of a new study published in Proceedings of the National Academy of Sciences write. “We use experiments and simulations to quantify how exhaled air is transported in speech. Phonetic characteristics introduce complexity to the airflow dynamics and plosive sounds, such as “P,” produce intense vortical structures that behave like “puffs” and rapidly reach 1 m. However, speech, corresponding to a train of such puffs, creates a conical, turbulent, jet-like flow and easily produces directed transport over 2 m in 30 s of conversation.”
The Princeton University researchers behind the new report went on to write that laughing and singing additionally carriers a considerable transmission hazard.
Staged phrases like, “Peter Piper picked a peck train of puffs,” were determined to pose a greater risk increase compared with phrases lacking prominent p sounds.
“Extended discussions, and meetings in confined spaces, mean that the local environment will potentially contain exhaled air over a significantly longer distance,” the authors continued.
Moreover, speaking in a loud voice for as little as 30 seconds projects aerosols more than six feet. Even speaking with an indoor voice can cast viral droplets more than six feet when done for longer periods of time.
This new data intercedes public health officials currently cautioning against re-opening hospitality markets without conditions.
“Lots of people have written about coughs and sneezes and the kinds of things you worry about with the flu,” Howard Stone, a professor of mechanical and aerospace engineering at Princeton explained in a release. “But those features are associated with visible symptoms, and with this disease, we are seeing a lot of spread by people without symptoms. Masks really cut this flow of tremendously. This identifies why (most) masks play a big role. They cut everything off.”
That “most” was recently covered by Ladders based on a counterfeit masks assessment published by The Centers for Disease Control and Prevention in conjunction with the US National Institute for Occupational Safety and Health.
Although 70% of K-95 masks imported from China do not meet safety standards, they are better than wearing nothing at all.
So long as a mask is able to block viral particles that are 30cm in size or larger (which most can), maintaining a distance of six-feet should keep you protected.