Scientists find a crucial factor in COVID-19 transmission

Knowridge Science Report
Knowridge Science Report
Credit: CC0 Public Domain

In a recent study published in Clinical Infectious Diseases, researchers found fine aerosols emitted during talking and singing may play a crucial role in COVID-19 transmission.

They found that fine aerosols (less than 5 micrometers, or μm) generated from these two types of activities contain more viral particles than coarse aerosols (more than 5 μm).

The fine respiratory aerosols may play a significant role in SARS-CoV-2 transmission, especially in an indoor environment.

The study is from the National University of Singapore. One author is Associate Professor Tham Kwok Wai.

The coronavirus disease 2019 (COVID-19) has been thought to spread primarily when an infected person coughs or sneezes, but little is known about its transmissibility through activities such as breathing, talking and singing.

In the study, the team tested 22 COVID-19 positive patients. The participants had to perform three separate expiratory activities on the same day.

These activities involved 30 minutes of breathing, 15 minutes of talking in the form of reading aloud passages from a children’s book, and 15 minutes of singing different songs, with rest between activities.

The participants had to carry out these three activities using specially designed exhalation collection equipment.

Aerosols were collected in two size fractions, namely coarse (more than 5 μm) and fine (less or equal to 5 μm).

The team found that COVID-19 patients who are early in the course of illness are likely to shed detectable levels of SARS-CoV-2 RNA in respiratory aerosols.

However, person-to-person variation in virus emission was high. Some patients surprisingly released more viruses from talking than singing.

The result provides direct measurements to show that besides respiratory droplets, virus particles emitted in exhaled breath and vocalization activities are likely important for transmitting SARS-CoV-2.

The findings suggest that exposure to fine-particle aerosols needs to be mitigated, especially in indoor environments where airborne transmission of SARS-CoV-2 is most likely to occur. Reducing exposure to fine respiratory aerosols can be achieved through many ways, such as universal masking, physical distancing, increased room ventilation, more efficient filtration and air-cleaning technologies.

If you care about COVID, please read studies about these two drugs may help you recover from severe COVID-19 and findings of most people hospitalized with COVID-19 have at least 1 symptom 6 months after falling ill.

For more information about COVID and your health, please see recent studies about new nasal spray could help prevent COVID-19 transmission and results showing what makes the COVID-19 virus highly infectious.

Copyright © 2021 Knowridge Science Report. All rights reserved.

Comments / 802

Jamie Bellimer

With all the vaccinated people, why are covid cases up 312% from October of last year when there was no vaccine? You all catching on yet?


It’s a virus we pretty’s much knew how viruses spread for the last 100 years. Fyi with all we have learned. We aren’t doing any better than we did in 1918

Bass Face

The crucial factor is that covid19 was created in a military lab as a bioweapon to kill us all and those that survive will get finished off by the poisonous DNA altering shot. 👎


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