Which vaccine should be avoided for Theresa, a woman on immunosuppressive therapy?

For a patient like Theresa who is on immunosuppressive therapy, the varicella vaccine should be avoided because it is a live attenuated vaccine. Individuals receiving immunosuppressive therapy have a weakened immune response, which puts them at higher risk for serious infections, including from live vaccines. The varicella vaccine can lead to actual infection in individuals who are immunocompromised, making it contraindicated in such populations.

In contrast, the other vaccines listed—PPSV23 (pneumococcal vaccine), Hepatitis B vaccine, and Tdap—are either inactivated or recombinant vaccines that do not contain live viruses. They can stimulate an immune response without the risk of causing the disease, making them safer options for patients undergoing immunosuppressive therapy. Therefore, the correct choice is to avoid the varicella vaccine to protect Theresa from potential adverse effects associated with her immunosuppressed state.