@eltonioni With respect to the good professors, they are I think making a leap possibly too far in making that statement based on the Danish study. Two groups, one masked, one not, showed a statistically insignificant difference in contracting covid. But this doesn't show how the members of each group spread it to others. For that you would need to measure the R rate in separate, matched populations.
Also, from the Danish paper itself https://www.acpjournals.org/doi/10.7326/M20-6817
, because if in doubt check the source:
The findings, however, should not be used to conclude that a recommendation for everyone to wear masks in the community would not be effective in reducing SARS-CoV-2 infections, because the trial did not test the role of masks in source control of SARS-CoV-2 infection. During the study period, authorities did not recommend face mask use outside hospital settings and mask use was rare in community settings (22). This means that study participants' exposure was overwhelmingly to persons not wearing masks.
Reduction in release of virus from infected persons into the environment may be the mechanism for mitigation of transmission in communities where mask use is common or mandated, as noted in observational studies. Thus, these findings do not provide data on the effectiveness of widespread mask wearing in the community in reducing SARS-CoV-2 infections.
“I am somehow less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops.” Stephen Jay Gould