[Vuejs]-Vue.js State Updates but View doesn't rerender

The problem is that data() does not react to changes in the store. You need to use a computed property to watch for state changes.
Example:

computed: {
    isDisabled: function ()  {
        return this.$store.state.ailment.length < 1
    }
}

You can also use getters if you need to manipulate the data and reuse it.
Getters Vuex