The findings from the randomised controlled trial, which is the gold standard when it comes to quality, revealed that surgical masks are much better than cloth ones.

The researchers are certain that these findings will put an end to any dispute about mask effectiveness as well.

Megan Ranney, an emergency medicine physician and a professor at Brown University stated:

“This was an incredibly challenging but important study to pull off.

“Anti-mask people keep saying, ‘Where’s the randomized controlled trial?’ Well, here you go.”

Researchers from Bangladesh and the United States evaluated the effectiveness of masks in 600 villages throughout Bangladesh.

It enrolled more than 342,000 participants, making it the largest randomized trial on mask use ever done.

Observational studies that compare solely mask-wearing behaviors to infection rates in different places can be perplexing due to a variety of additional variables.

However, randomized controlled trials, in which participants are randomly allocated to receive or not receive medical intervention, are regarded as the most reliable method of giving evidence.

The issue is that they are costly and difficult to conduct, especially for activities such as mask-wearing.

Between November 2020 and April 2021, around 178,000 people received the “intervention,” whereas 164,000 did not.

Those in the intervention group received complimentary masks and educational materials on the importance of mask use.

Additionally, community leaders reminded residents in person to wear their masks for an eight-week period.

However, those in the control group, the 164,000 individuals who were not included in the intervention group, did not obtain any of these benefits.

The researchers stationed observers in the community to determine how many people wore masks appropriately and engaged in social distancing behaviours in public spaces such as mosques, markets, and tea stalls.

These observations were made on a weekly basis. 

Five and nine weeks after the trials began, the researchers asked participants whether they were experiencing any typical coronavirus symptoms.

Then, about 10 to 12 weeks after the trial started, they took blood samples from the participants who were symptomatic and tested them for SARS-CoV-2 antibodies.

The masking interventions made proper mask use triple, going from 13.3 percent in the control group observations to 42.3 per cent in the masking intervention group.

Different villages were also given either cloth masks or surgical masks.

In the villages that were given surgical masks, symptomatic infection was reduced by 11.2 percent compared with the control group – which is being reported as “unequivocal” evidence of their effectiveness.

This percentage was even higher in older adults, with those 60 years or older who were given free surgical masks and some other interventions, symptomatic infection was reduced by 34.7 percent compared with the control group. 

But they did not find that cloth masks reduced symptomatic infection compared with control groups.

The study was posted as a preprint to the Innovations for Poverty Action and is being peer-reviewed for publication in the Science journal.

Image Credit: GEtty