Honestly, just about the ONLY thing you need to defend against Romero Zombies.
Handy, quick, quiet and never needs to be reloaded. Better reach than a knife or tomahawk. More utility than a battle axe. Faster action than a sword. Light enough to hike and run with. Better penetration than a blugeon. Can be a utilitarian substitue for all those weapons and more.
Also, for backup:
I was so ahead of the times. Almost seven years ago.... I feel so old.
PS, who are all these people?
This is a hell of a long month...
Nevertheless, here's some actual grappling related zombie information from Stephen Kesting: