the federal government y constantly uses very conservative estimates in assessing risk and offering guidelines. not to get too off track but a good example is the federal guidelines on cooking red meat. The federal government tells you that red meat must be cooked to 145 degrees in order to be considered "safe" to eat. the reality is that a good rare steak can and should (imo) be cooked to an internal temp of 120 degrees. is 145 "more safe" yes, but an internal temp of 120 degrees is more then safe. so like masks, herd immunity, etc, the question is how much risk does one want to take and then what guidelines do you propose base on those assumptions of risk.
