Face masks, even medical ones, are not 100% effective at eliminating coronavirus contagion risk entirely and preventing the spread of the virus, although they can offer protection from airborne coronavirus particles, according to a new study led by Japanese researchers at the University of Tokyo.
As explained in the study report, published in the Japan Times, after building a secure chamber with mannequin heads facing each other, the scientists equipped one head with a nebulizer that simulated coughing and expelled actual coronavirus particles while the other imitated natural breathing, with a collection chamber for viruses coming through the airway.
The cotton mask, on the receiver head, reduced its viral uptake by up to 40% compared with no mask, while the medical-used N95 mask blocked up to 90%.
However, even when the N95 mask was taped to the face of the mannequin, the study showed that some virus particles still managed to get through.
The researchers also discovered that more than 50% of the virus transmission was blocked when the cotton and surgical masks was attached to the coughing head.
“There was a synergistic effect when both the virus receiver and virus spreader wore masks,” the researchers wrote in a study published on Wednesday.
This study emphasizes the importance of wearing a mask, for both for transmitters and receivers, considering, as the study showed, that masks are reducing the spread of the virus, from one way and the other, even if there is still a possibility for the virus to get in.
Face masks are still shown to be the most effective means of slowing the spread of the virus, and medical bodies worldwide recommend wearing them and maintaining social distancing measures.
There has been a growing consensus among health experts that the COVID-19 virus can be spread through the air.
The US Centers for Disease Control and Prevention (CDC) revised its guidance this month to say the pathogen can linger in the air for hours. Moreover, according to another Japenese study, humidity was said to have a significant effect on the airborne coronavirus particles dispersion in the air.
The CDC study, conducted in July, found that over 70% of the 154 "case-patients," who had tested positive for COVID-19, were infected despite making efforts to abide by CDC guidelines, including the wearing of face masks.It is possible that some of the infections may have been caused by removing face coverings for food or drink. Another possibility is airflow, as “direction, ventilation and intensity of airflow might affect virus transmission, even if social distancing measures and mask use are implemented according to current guidance,” according to the CDC report.