Published April 20, 2021

International Journal of Environmental Research and Public Health

Review of 65 studies:

44 found adverse health effects from masks that were statistically-significant (beyond random chance)

22 completed before 2020
22 completed during pandemic
8 Authors - Backgrounds in:

Molecular and Cellular Anatomy,
Pathology,
Neuroscience,
Neurosurgical Pathophysiology, and
Psychology.
Many side effects are measurable and statistically significant.

Some are "subthreshold" effects when masks are worn for short durations in some healthy people, but prolonged use raises concerns, and others experience side effects quicker.
Side effects range from minor to potentially serious, including neurological effects like impaired thinking, impaired concentration, and drowsiness; microbiological build-up, tooth decay ("mask mouth"), and chronic skin irritation.
Neurological Side Effects, Section 3.3:

"In a mask experiment from 2020, significant impaired thinking (p < 0.03) and impaired concentration (p < 0.02) were found for all mask types used (fabric, surgical and N95 masks) after only 100 min of wearing the mask [29]."
Long-term Concerns: Section 3.1

"It is known from pathology that not only supra-threshold stimuli exceeding normal limits have disease-relevant consequences. Subthreshold stimuli are also capable of causing pathological changes if the exposure time is long enough."
Internistic Side Effects - Section 3.2

"Since the symptoms were described in combination in mask wearers and were not observed in isolation in the majority of cases, we refer to them as general Mask-Induced Exhaustion Syndrome (MIES)..."
Masks and Children: Section 3.14

"Special attention must be paid to the respiration of children, which represents a critical and vulnerable physiological variable due to higher oxygen demand, increased hypoxia susceptibility of the CNS, lower respiratory reserve..."
Pathogens Growing in Masks: Section 3.12

"The warm and humid mask microclimate favors the accumulation of various germs on and underneath the masks [86]... After only 2 h of wearing the mask, the pathogen density increases almost tenfold in experimental observation studies."
Comparison with Sick Building Syndrome - Section 4

"Temperature, carbon dioxide content of the air, headaches, dizziness, drowsiness and itching also play a role in Sick Building Syndrome."
Conclusions - Section 6

"Wearing masks does not consistently cause clinical deviations[,but]a long-term pathological consequence with clinical relevance is... expected owing to a longer-lasting effect with a subliminal impact and significant shift in the pathological direction."
Conclusions - Section 6 (con't)

"[We found] an increase in direct short-term effects with increased mask-wearing time for: carbon dioxide retention, drowsiness, headache, feeling of exhaustion, skin irritation (redness, itching) and microbiological contamination."
More Mask-related Information:

Please see my pinned tweet - a thread of threads

For CO2 vs Cognitive Performance: https://twitter.com/Matthew94091812/status/1371659908995764226
End of Thread - Thank you for reading.

Replies and additional related information may follow this thread.
You can follow @Matthew94091812.
Tip: mention @twtextapp on a Twitter thread with the keyword “unroll” to get a link to it.

Latest Threads Unrolled: