The Swiss Policy Research has published a statement about the Danish mask study, including links that expound the study. 

The Danish randomized controlled trial on the real-world efficacy of face masks against coronavirus infection – the first of its kind – has now been published in the Annals of Internal Medicine. As expected, the trial found no statistically significant benefit of wearing a face mask. The study used “high-quality surgical masks with a filtration rate of 98%”.

 

Read more here on Swiss Research Policy