App note from ON Semiconductors about eFuses’ ability to block reverse voltage. Link here (PDF)
One area in which they (eFuses) differ in performance is reverse polarity protection. While a TVS device and polyfuse will protect against reverse voltages, the nature of an integrated semiconductor device does not inherently allow for this type of protection.
This simple circuit allows the device to protect against reverse voltage situations by simply blocking the reverse voltage. This is equivalent of the action of a poly fuse only with less leakage. In comparison to a mechanical fuse, this is a far superior solution since the mechanical fuse will not reset and this circuit will automatically reset when the correct voltage is applied.