The one immutable fact about war down the ages has been that only the healthy are deemed fit for the front.
The asymmetrical tactics of the Covid-19 battle have already ordained that this too will be turned on its head.
They have produced arguably the oddest conscription campaign ever: as there won't be time to test everyone, as the spread outstrips the capacity of labs and health services to cope, it may be best to assume one has the virus.
Members of the public, who by and large become the foot soldiers tasked with carrying the fight, are being enlisted and prepped for the trenches on the presumption they are already infected.
Once one assumes one is sick, logic dictates one isolates and withdraws from contact; thus slowing down the outbreak.
And some slight advances are being made.
According to the HSE's Peter Holohan, doctors carrying out contact tracing believe that confirmed cases are now reporting fewer contacts.
This, he said, was an encouraging sign that people were following the public health guidance.
But circumstances dictate further comprehensive changes in behaviour may yet be demanded.
Their sole aim would be to further co-ordinate resources and ensure critical needs are met to protect us.
Health Minister Simon Harris accepts further recommendations may be made this week in relation to physical distancing and public gatherings. If tragic scenes like the heartbreaking ones we are seeing in Italy are to be prevented here, they will be more than justified.
But, as Taoiseach Leo Varadkar and Mr Harris have reasonably pointed out, any such measures must be grounded in scientific fact and not driven by hysterical Twitter campaigns or desperate political point scoring.
Empathy, not scapegoating, will best serve our situation.
Yes, their have been outliers, and the behaviour of some is indefensible.
But, as Mr Harris said, the sense of solidarity being displayed around the country is impressive.
The dedication of those in the health and service sectors, and the general sense of social cohesion should be saluted.
Personal decisions to create a physical distance rather than mandatory measures would always be preferable. But public safety has to be protected.
As 'The Washington Post' newspaper has acknowledged: "A spiky, round or elliptical juggernaut, measuring from 60 to 140 billionths of a metre across, has turned the world upside down in just a few weeks."
There is little reason to believe the pandemic is likely to end in the near future.
As the epidemiologists tell us, this is nothing if not an opportunistic parasite with an unrivalled ability to pounce on any weakness in our defences.
But it is not invincible, and the more we wash our hands and observe the expert advice we are given, the better chance we have to terminate its malign ascendancy.