Social distancing and handwashing were also effective at lowering the number of cases, but wearing masks was the most effective tool against the coronavirus.
“Personal and social measures, including handwashing, mask wearing, and physical distancing are effective at reducing the incidence of COVID-19,” the study authors wrote.
The research team, which included public health and infectious disease specialists in Australia, China, and the U.K., evaluated 72 studies of COVID-19 precautions during the pandemic. They later looked at eight studies that focused on handwashing, mask wearing, and physical distancing.
Among six studies that looked at mask wearing, the researchers found a 53% reduction in COVID-19 cases. In the broader analysis with additional studies, wearing a mask reduced coronavirus transmission, cases, and deaths.
In one study across 200 countries, mandatory mask wearing resulted in nearly 46% fewer negative outcomes from COVID-19. In another study in the U.S., coronavirus transmission was reduced 29% in states where masks were mandatory.
But the research team couldn’t analyze the impact of the type of face mask used, the frequency of mask wearing, or the overall compliance with wearing face masks.
Among five studies that looked at physical distancing, the researchers found a 25% reduction in the rate of COVID-19. A study in the U.S. showed a 12% decrease in coronavirus transmission, while another study in Iran reported a reduction in COVID-19 mortality.
Handwashing interventions also suggested a substantial reduction of COVID-19 cases up to 53%, the researchers wrote. But in adjusted models, the results weren’t statistically significant due to the small number of studies included.
Other studies found significant decreases related to other public health measures, such as quarantines, broad lockdowns, border closures, school closures, business closures, and travel restrictions. Still, the research team couldn’t analyze the overall effectiveness of these measures due to the different ways the studies were conducted.
The study lines up with other research conducted so far during the pandemic, the research team wrote, which indicates that wearing masks and physical distancing can reduce transmission, cases, and deaths.
That said, more studies are needed, particularly now that vaccinations are available and contagious coronavirus variants have become prevalent.
“Further research is needed to assess the effectiveness of public health measures after adequate vaccination coverage has been achieved,” they wrote.
“It is likely that further control of the COVID-19 pandemic depends not only on high vaccination coverage and its effectiveness but also on ongoing adherence to effective and sustainable public health measures,” they concluded.
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