From Cochrane Library Reviews: Tom Jefferson et al.,
Physical interventions to interrupt or reduce the spread of respiratory viruses
PLAIN LANGUAGE SUMMARY
Do physical measures such as hand-washing or wearing masks stop or slow the spread of respiratory viruses?
Key messages We are uncertain whether wearing masks or N95/P2 respirators helps to slow the spread of respiratory viruses based on the studies we assessed. Hand hygiene programs may help to slow the spread of respiratory viruses.
A search of recent Cochrane Library reviews has no reviews on social distancing or nutritional interventions.
Front Line COVID-19 Critical Care Alliance (FLCCC) has a prevention regimen that may be beneficial
https://covid19criticalcare.com/treatment-protocols/i-prevent-protect/