Yes there is uncertainty, and therefore the study was unable to come to decisive conclusions about mask effectiveness.
Weasel words are expected when people have to back track from prior claims.
If masks were ineffective, professionals would not wear them in laboratories or operating rooms.
There are no open wounds in surgery that come back infected with a virus. The wound infections are bacterial. You should know that
My mother had 2 knee replacement surgeries. (for you outsiders, "bone" surgery is at a higher risk because infection in a bone is tougher to treat than soft tissue wound infections)
Then she tripped and fell fracturing her femur. So they removed her knee prrosthesis and installed one with a long femoral shaft.
She got a wound infection. Over the next year she was in surgery a few times to drain. Doc said amputate. We said NO!
She was on a bouquet of anti-biotics for MRSA infection.
The masks must not have worked in OR
One day we had an evangelist in Church from Florida. He and I asked The Lord to heal mom. Thank you Jesus.
I let it go. Couple weeks later my sister (former hospital Pharmacy manager) saw her. I asked. No longer any drainage from the wound, The skin closed. no infection. Healed.
Lot of the antibiotics junk damaged her hearing. After healing and coming off the antibiotics, her hearing improved.
