It's only taxable income if you were previously able to deduct it and get a tax benefit it on your tax return.
This is rare, unless you were self-employed and claimed the self-employed healthcare deduction.
For most people, for the premiums to have been deducted on the tax return, you must itemize deductions on Schedule A, and your unreimbursed medical expenses must exceed 10 percent of your adjusted gross income (AGI). Then, you can only deduct the amount by which your unreimbursed medical expenses exceed this 10 percent threshold (7.5% of AGI for age 65 and older until 2017).
