A study has been published in the journal Nature Science which suggests that wearing surgical face masks give us lots of protection from the transmission of seasonal coronaviruses and influenza virus.
Importance of wearing face masks to get protection from influenza virus has already been stressed by many studies. What we did not know how it protects us from the transmission of other respiratory viruses, including seasonal coronaviruses.
More evidences were needed to determine whether masks can specifically prevent the transmission of SARS-CoV-2, which is closely related to seasonal coronaviruses.
Researchers, including those from the University of Hong Kong researchers recruited 246 people with suspected respiratory viral infections to breathe into a machine — the Gesundheit II — to compare the relative amount of virus in exhaled breath with or without a face mask.
They found that in 111 people whose infections by either coronavirus, influenza virus or rhinovirus were confirmed, masks reduced detectable virus in respiratory droplets and aerosols for seasonal coronaviruses, and in respiratory droplets for influenza virus.
However, researchers found that masks don’t not reduce the emission of rhinoviruses. SARS-CoV-2 and seasonal coronaviruses are closely related and may be of similar particle size.
The researchers found that masks can contribute to slowing the spread of SARS-CoV-2 when worn by people infected with the virus.
Previous research had shown that respiratory viral infections, including those caused by coronaviruses, spread between humans mostly through close contact.
The researchers noted that there is no direct evidence of how influenza and coronaviruses spread between humans who are in close proximity — whether by direct contact, large respiratory droplets, or through breathing another person’s exhaled breath.
Respiratory viruses can also survive in the environment and potentially spread through indirect contact, the researchers explained.
Larger respiratory droplets, which fall near the source, as well as aerosols of smaller fine particles can both contain virus and cause short-range transmission, they said.
In addition, aerosols can remain in the air for longer and potentially transmit infection over longer distances, particularly if they are generated at higher concentration or if there is little ventilation. The team noted that non-pharmaceutical measures, such as social distancing, handwashing, ventilation, and face masks, could be important measures to prevent viral transmission.