The two available Tetanus/reduced diphtheria toxoid/acellular pertussis (Tdap) vaccine products in the U.S. are Boostrix and Adacel. Neither were originally approved in older adults age 65 and older. Boostrix received FDA-approval for use in this age group in July 2011, but Adacel never has.
However, in June 2012 ACIP issued new guidance recommending Tdap for all adults age 65 years and older.
"When feasible, Boostrix should be used for adults aged 65 years and older; however, ACIP concluded that either vaccine administered to a person 65 years or older is immunogenic and would provide protection. A dose of either vaccine may be considered valid."
Bottom line: Regardless of which Tdap product is stocked at your institution, both are considered safe to use in adults 65 years and older.
References
Centers for Disease Control and Prevention (CDC), “Updated Recommendations for Use of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis (Tdap) Vaccine in Adults Aged 65 Years and Older - Advisory Committee on Immunization Practices (ACIP)," MMWR Morb Mortal Wkly Rep, 2012, 61(25):468-70. [PMID 22739778]
