Now that every village has been updated, zombie villages don't exist anymore. They are replaced by new villages, which contain non-infected villagers.

In the code, older villages were deleted when updating to new villages. Zombie Villages were coded with the older villages, and new villages can't be a zombie village (Villagers now spawns with Jigsaw blocks, which never spawn zombie villagers).

Edit : partially fixed in 19w04a for desert and taiga villages