I think the profit in most pharmacy's immunization program is from the medical administration fee of about $20. This assumes you don't have to pay for an extra pharmacist's time to administer it.
The story with Zostavax is in the product package insert. Elderly people's immune system don't react to the vaccine often and this increases as they age. Vaccine efficacy is 64% for age 60-69 and is as low as 18% in age 80+. So far far less effective than say flu shots.
I know several pharmacist used to object to this when few insurance companies would pay for it. But if your patient has it 100% covered then why not administer it? You could prevent someone from getting an excruciating painful case of shingles.
I believe the profit for most immunizations is 20 dollars. I am not sure what insurances are reimbursing in other states as I have never administered it in an independent setting, and I am sure reimbursements have changed the last year or so.
For the Zostavax vaccine, there are a few things to keep in mind.
It can be extremely profitable if people fork out the money for it or if you get good reimbursements. I heard the pain with shingles is crazy (like going into labor). Most people who saw their friends or family get it is willing to pay cash for it if their insurance does not cover it. At 220 dollars, that is 35 dollars profit. It is like filling a bottle of Atripla or Procrit which can cost thousands....
I heard that it is not covered under Medicare Part B anymore so doctors are sending people looking for the vaccine to pharmacies because it is covered under Part D. If you can be a guarantee source (as it needs a freezer to store which most pharmacies do not have) of new customers.
I also heard that if the vaccine is expired, you can return it for almost full credit... (I think 80 percent). There is a process that I forgot, but its something like waiting for it to be expired after a few months, and then returning it directly to Merck. I would talk to your local Merck drug rep about that.
While the efficacy is low as age progresses...., a thing to keep in mind is that the symptoms with the shingles is not as bad as someone without. There is not enough data on how much of a difference, or to what level but I would keep that on the back of my head.
Lastly, I concur with what Monsterdaddy is saying... but a reminder that the pharmacist is a FIXED cost. The cost that you just have to pay for is the freezer, the rent on the space for the freezer if your pharmacy has limited amount of space, and electricity for the freezer. it sucks because I don't know of any other drugs that requires sub zero freezing. I am guessing you would need to at least give out one shot a month to make it worth your while.