For the author: The solution is to ask for their sources - not to speculate that it’s all a sham (while conveniently also not providing any data to back up such a claim.) Meanwhile a single search pulls a possible source for the 80% figure: https://www.cdc.gov/coronavirus/2019-ncov/science/science-br... But talking about that source is inconvenient to the author because it provides ample support over a range of real…
"The intervention increased proper mask-wearing from 13.3% in control villages (N=806,547 observations) to 42.3% in treatment villages (N=797,715 observations) (adjusted percentage point difference = 0.29 \[0.27, 0.31\]). This tripling of mask usage was sustained during the intervention period and two weeks after. \[...\] The proportion of individuals with COVID-like symptoms was __7.62%__ (N=13,273) in the intervention arm and __8.62%__ (N=13,893) in the control arm." - ["The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh" (2021)](https://www.poverty-action.org/sites/default/files/publicati...)
"SARS-CoV-2-naïve vaccinees had a 13.06-fold (95% CI, 8.08 to 21.11) increased risk for breakthrough infection with the Delta variant compared to those previously infected, when the first event (infection or vaccination) occurred during January and February of 2021." - ["Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections" (2021)](https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v...)