Vaccines
Vaccines is a special upgrade in Loot Grinder, the free medieval idle clicker.
What it does
Immunise the kingdom — the plague can no longer claim your peons. (Immunise the kingdom — the plague can no longer claim your peons.)
Cost
It costs 3B loot and is a one-time purchase.
Why it’s useful
Fewer peons lost to disaster means your loot-per-second never craters mid-run — protection upgrades pay off as insurance on everything else you’ve built.