Practitioners licensed under this chapter shall maintain health records, as defined in § 32.1-127.1:03, for a minimum of six years following the last patient encounter. However, such practitioners are not required to maintain health records for longer than 12 years from the date of creation except for (i) health records of a minor child, including immunizations, which shall be maintained until the child reaches the age of 18 or becomes emancipated, with a minimum time for record retention of six years from the last patient encounter regardless of the age of the child or (ii) health records that are required by contractual obligation or federal law to be maintained for a longer period of time. Health records that have previously been transferred to another practitioner or health care provider or provided to the patient or his personal representative are not required to be maintained beyond such transfer or provision.