if you itemized deductions and took a deduction for those premiums to the extent you received a benefit from the deduction the refund is taxable.
in the case of itemized deductions, the taxable amount will generally be the lesser of the refund or line 4 of schedule A for the year of the deduction
if you took a self-employed health insurance deduction for the premiums the refund is taxable to the extent of the lesser of the SE health insurance deduction or the refund
