In a controversial result, researchers in Denmark have shown real-world evidence that masks do not protect against becoming infected with COVID.
4860 participants completed the study in Denmark, which at the time had a 2% infection rate. Half received surgical masks and were told to wear them outside while the other half were told not to wear masks. The researchers had hoped to see the masks halving the infection rate among wearers, but 1.8% of mask wearers became infected with COVID vs 2.1% of non-mask wearers.
“Our study gives an indication of how much you gain from wearing a mask,” said lead author Dr Henning Bundgaard, a cardiologist at the University of Copenhagen. “Not a lot.”
The results were met with scepticism by some, and noted that the lower prevalence of COVID in Denmark at the time made differences hard to detect.
Dr Thomas Frieden, chief executive of Resolve to Save Lives, an advocacy group, and former director of the CDC outlined the limitations of the study, saying, “There is absolutely no doubt that masks work as source control. The question this study was designed to answer is: Do they work as personal protection?” Frieden said that the answer to those questions lay in the amount of virus exposure and the nature of the masks involved.
“An N95 mask is better than a surgical mask,” he said. “A surgical mask is better than most cloth masks. A cloth mask is better than nothing.”
Dr Christine Laine, editor in chief of the Annals of Internal Medicine, characterised the evidence that masks were protective of wearers as weak.
“These studies cannot differentiate between source control and personal protection of the mask wearer,” she said.
She added that the new study reinforced the need for other methods, such as social distancing. Masks “are not a magic bullet,” she said. “There are people who say, ‘I’m fine, I’m wearing a mask.’ They need to realise they are not invulnerable to infection.”
Source: Japan Times
