Study finds mask-wearing dramatically reduces transmission of COVID-19

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Researchers say their results show how important it is for consumers to protect themselves

Researchers from the University of Hong Kong have discovered that wearing a surgical mask can reduce transmission of COVID-19 by as much as 75 percent. 

During a time when some are questioning the effectiveness of wearing a mask outside of medical settings, the researchers say the findings underscore the importance of wearing them during normal activities. 

In a study involving 52 hamsters (which were chosen as subjects because they have similar enzyme receptors to humans), the researchers found that surgical masks dramatically reduced the spread of respiratory droplets or airborne particles. 

“The findings implied to the world and the public is that the effectiveness of mask-wearing against the coronavirus pandemic is huge,” Dr. Yuen Kwok-yung, a leading microbiologist from Hong Kong University who helped discover the SARS virus in 2003, told reporters on Sunday.

Study details 

For the study, the team separated two groups of hamsters. One cage contained healthy hamsters and the other contained hamsters infected with COVID-19. 

Two-thirds of the hamsters with no mask barriers became infected with the virus within a week. The infection rate fell to 16.7 percent when the mask was placed over the cage containing infected subjects, and the infection rate went up to 33 percent when the mask was only used to cover the healthy hamsters’ cage.  

“In our hamster experiment, it shows very clearly that if infected hamsters or humans — especially asymptomatic or symptomatic ones — put on masks, they actually protect other people. That’s the strongest result we showed here,” Yuen said. “Transmission can be reduced by 50 (percentage points) when surgical masks are used, especially when masks are worn by infected individuals.”

A practical move

Health officials have dispersed conflicting recommendations on mask-wearing in recent months, initially saying that masks should be worn only by health care workers. The CDC now recommends that all individuals wear a mask. 

With states easing stay-at-home guidelines, the researchers say the findings highlight the need to wear a mask during necessary public outings. 

“Up to this stage, we do not have a safe and effective vaccine. What remains practical is still either social-distancing measures or wearing masks,” Yuen added.

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