A team of researchers from Texas and California compared trends in Covid-19 infection rates in Italy and New York, before and after a face mask. In both locations, infection rates began to drop only after mandatory mask measures were taken, according to a study published Thursday in the Proceedings of the National Academy of Sciences.
The researchers calculated that wearing face masks prevented more than 78,000 infections in Italy between April 6 and May 9, and more than 66,000 infections in New York between April 17 and May 9.
“Wearing face masks in public is the most effective means of preventing interpersonal transmission, and this cheap practice, combined with simultaneous social distancing, quarantine and contact seeking, represents the most likely combat opportunity to stop the COVID-19 pandemic before vaccine development,” they wrote. .
The researchers evaluated the effectiveness of various strategies to stop the spread of infection and determine how the virus mainly spreads. Viruses can be spread by direct contact when a person coughs or sneezes at another person; indirect contact, when a person coughs or sneezes at an object that is then touched by another person; or in the air through large droplets that fall quickly to the ground and tiny droplets, called aerosols, that can travel several feet and hang in the air for a while.
To determine the main mode of transmission of the virus, researchers analyzed trends in the rate of infection in the three epicenters of the pandemic – Wuhan, China, Italy and New York. They reviewed the mitigation measures applied in these places, such as extensive testing, quarantine, seeking contact, social distance, and mandatory use of face masks.
The researchers then compared the time when these measures were applied. In China, all measures were taken at the same time. In contrast, mitigation measures have been applied at different times in Italy and New York.
This allowed researchers to assess the relative effectiveness of the measures. They found that infection rates were in Italy, and NYC began to slow only after face masks became mandatory, not after a lock was concluded in Italy or after home stay orders took effect in New York City.
Regions in northern Italy began requiring face masks on April 6, and mandatory use across the country was ordered on May 4. The use of face masks in New York City is required from April 17th. The researchers calculated the number of prevented infections between those dates and May 9th.
“Covering the face prevents both airborne airborne transmission by blocking the atomization and inhalation of virus-carrying aerosols and contact transmission by blocking viral droplet spillage,” they write. “On the other hand, social distancing, quarantine and isolation, combined with hand disinfection, minimize contact (direct and indirect) transmission but do not protect against airborne transmission.”
The study noted that unlike China, wearing face masks is not popular in much of the Western world during the early outbreak of a pandemic. But researchers said the evidence shows the masks work on a slow spread.
The researchers wrote that both the World Health Organization and the U.S. Centers for Disease Control and Prevention have emphasized the prevention of contact transmission, but both organizations have largely ignored the importance of airborne transmission routes.
“Current mitigation measures, such as social distancing, quarantine, and isolation implemented in the United States, are not in themselves sufficient to protect the public,” the researchers wrote.
A team of five researchers from Texas A&M University, the University of Texas, the University of California, San Diego and the California Institute of Technology.
Italy has been in jail across the country since March 9, but Prime Minister Giuseppe Conte told a news conference Thursday night that the country is further easing coronavirus closure measures to allow professional sporting events, such as the Coppa Italia football match, to continue behind closed doors. from Friday.
Other facilities may also reopen as of June 25, including summer camps, kindergartens, bookmakers and bingo halls, Conte said, announcing that he has just signed a decree facilitating further closure measures. Non-professional sports that involve physical contact can also continue.
CNN’s Livia Borghese contributed to this report.