Except as otherwise specifically provided by the laws of this state, the regular term of office of each county officer, when the officer is elected for a full term, shall commence on the first of January next succeeding the officer’s election and each such officer shall qualify and enter upon the discharge of the officer’s duties on the first of January next succeeding the date of the officer’s election. If the office to which an officer is elected was vacant at the time of the officer’s election or becomes vacant prior to the date fixed for the commencement of the officer’s term, the officer may qualify and enter upon the duties of the office forthwith even though the officer was not elected to fill such vacancy. If an officer is elected to fill an unexpired term in an office then held by an appointee, such officer may qualify and enter upon the discharge of the duties of such office at any time after receiving a certificate of election to that office but not later than the first Monday in January next succeeding the date of the officer’s election to the unexpired term of office.