Physical interventions to interrupt or reduce the spread of respiratory viruses
cochranelibrary.com
cochranelibrary.com
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...
I copied the title into their search field, and went to the first hit from there. Looking at the date, that should be the thing.
My favorite, meta-studies! And nothing seems to help based on this study of studies. I find that "it's best to carry on as usual" is hard to reconcile with the absolute lack of a flu season 2020-21 and 2021-22. Something worked, because there was essentially zero influenza those 2 years, in the USA and elsewhere.
Several things come to my mind:
Isolation by lock-down, or general avoidance of strangers, eating/going out, masses of people, limiting in person shopping, remote work, avoiding public transportation.
Validity of numbers, prioritization of tests.