Are Medicare Part A premiums tax deductible if I have not yet signed up to receive Social Security payments?

I am 66, retired, and collect a pension, but have not yet signed up to collect Social Security payments.  I had to start paying for Medicare last year when I turned 65.  Since I am not collecting Social Security, are the premiums I pay for Medicare (Part-A) tax deductible?  Previous answers say "no, if I'm covered under Social Security", but what does covered under Social Security mean exactly...no, because I qualify for SS or no, if I start collecting SS payments?