The science is solid, and not just counting medical science, that masks don’t contain virion:
This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated.”
Cloth masks can increase infection
From the WHO: There is limited evidence that wearing a medical mask by healthy individuals in the households or among contacts of a sick patient, or among attendees of mass gatherings may be beneficial as a preventive measure.14-23 However, there is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19.
Prolonged wearing of the surgical mask causes loss of intellect potential and cognitive performance due to a decrease in blood oxygen and subsequent brain hypoxia. Note – some changes may be irreversible.
“Report on surgical mask induced deoxygenation during major surgery”
“Seventy percent of the patients showed a reduction in partial pressure of oxygen (PaO2), and 19% developed various degrees of hypoxemia. Wearing an N95 mask significantly reduced the PaO2 level”
“Wearing N95 masks results in hypooxygenemia and hypercapnia which reduce working efficiency and the ability to make correct decision.”
“Medical staff are at increased risk of getting ‘Severe acute respiratory syndrome’ (SARS), and wearing N95 masks is highly recommended by experts worldwide. However, dizziness, headache, and short of breath are commonly experienced by the medical staff wearing N95 masks. The ability to make correct decision may be hampered, too.”
“Chronic hypoxia-hypercapnia influences cognitive function”
“Hypercapnia status has been shown to predict mild cognitive impairment https://www.nature.com/articles/s41598-018-35797-3
Chronic hypoxia – hypercapnia has been seen as a cause of cognitive impairment
Fit testing matters less vs it’s an N95 mask: https://www.ncbi.nlm.nih.gov/pubmed/21477136
Masks don’t seem to impact family infection as much: https://www.ncbi.nlm.nih.gov/pubmed/28039289
Medical or N95 isn’t that different: https://www.ncbi.nlm.nih.gov/pubmed/31479137
Cloth masks worse than surgical masks for anything <2.5 uM:
Particle size breakdown and fabric differences for cloth masks and particle penetration:
In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.