Notwithstanding subdivision 2 (b) of § 38.2-3503 or the provisions of § 38.2-3514.1, an insurer that issues a Medicare supplement policy shall not deny a claim for losses incurred more than six months from the effective date of coverage on the grounds that a condition existed prior to the effective date of coverage regardless of the application form used. Except as so provided, the policy or contract shall not include wording that would permit a defense based upon preexisting conditions.