If 80% of people wore masks when leaving their homes, COVID-19 transmission rates would be significantly better contained, a UC Berkeley researcher and his team found in a study.
Dekai Wu, also known as De Kai, a researcher at UC Berkeley’s International Computer Science Institute and a professor at the Hong Kong University of Science and Technology, first came up with the idea for the study when he noticed the difference in COVID-19 response between California and Hong Kong, especially in mask use. His research group is an interdisciplinary team of global researchers. They found there is almost a 100% correlation between countries that have implemented early universal masking policies and those that have suppressed the spread of the coronavirus.
“Ninety-nine percent of people are walking around wearing masks in Hong Kong. In Hong Kong, we’ve actually never had to have shelter in place because we’ve done the other things right.”De Kai
The study uses two types of models to predict the impact of masks on infection rates. The first is called the susceptible-exposed-infected-recovered, or SEIR, model. It’s a traditional epidemiological method that sorts theoretical individuals into one of the four categories according to who they come in contact with based on mathematical equations. When susceptible people interact with infected individuals, they become exposed and eventually infectious themselves, which allows them to spread the disease to other people until they recover.
But De Kai says that mathematical equations make it hard to account for strategies such as social distancing. So he developed a second method called agent-based modeling, or ABM. This method accounts for these variables more accurately.
Both methods showed that masks are highly effective if universal mask policies are implemented by day 50 of a region’s outbreak and if 80% of the population wears a mask.
Included in the study is a link to an online simulator where people can watch the results of the experiment change by toggling the percentage of the population that wears masks and how effective the masks are, among other variables.
De Kai said he wanted people to be able to visualize the research, as the effects of masking policies are logarithmic and can be hard to understand.
Obviously, wearing masks alone is not enough. Social distancing and quarantine measures are also important. But if we look at Japan or Hong Kong, where masking is universal, we’ll see these countries have eschewed massive lockdowns and even contact tracing. But their statistics are one of the best in the world, with Japan’s death rate a mere 2% of the U.S. numbers.
Wearing a mask has become an automatic response for many Asian countries after the SARS outbreak in 2002–2004. The Japanese, the Taiwanese, the Koreans have all learned from their mistakes.