Yep, I had this conversation with my ob and you can definately get it more than once. Often in adults it will appear as shingles rather than chicken pox, but it's the same virus. I had it as a kid but we also checked my immunity in my prenatal blood work and I am still immune, but only just (ie I think they explained it as I do have the antibodies but in low numbers). If I decide to fall prg again, I will be having a top up vaccine for next time, isn't worth the stress this causes.

If I were you, I'd talk to you Dr, see what they say and then perhaps talk to your employer about your concerns. You have the right to feel safe at work and free from the risk of illness.