This goal of this study is to assess the safety and immunogenicity of recombinant zoster virus in young adult solid organ transplant recipients. In this study, participants will receive the recombinant zoster vaccine. They will be monitored for adverse events and tested for antibody and cellular immunity.

This is an open-label, non-blinded study to assess the safety and immunogenicity of the Recombinant Zoster Vaccine (RZV) in young adult recipients of solid organ transplants (heart, liver, kidney). After obtaining consent, the patient will have pre-vaccine baseline Varicella Zoster Virus (VZV) anti-gE antibody testing performed by the Weinberg lab and then will be given first dose of vaccine. Participants will be brought back 30-60 days post-vaccine for follow up testing and second dose of vaccine. Participants will then be brought in for follow-up testing at 1-2 months, 6 months, and 12-15 months after receiving 2nd dose of vaccine. Testing for both antibody and cellular immunity to VZV will be performed throughout the study. Telephone, electronic and in-person follow up will be conducted to assess for any clinical signs of VZV reactivation, any vaccine-related side effects or any signs of acute rejection.

Inclusion Criteria:

• 19 years of age or older and willing to provide written informed consent for the study participation.
• Prior recipient of solid organ transplant more than one year prior to participation.
• Stable immunosuppressive medication regimen for last 6 months prior to participation
• Participant must have a working telephone number, email address or patient Electronic Health Record (EHR) portal access and be willing to be contacted for study follow-up by any of these means.
• For participants of childbearing potential, use of effective pregnancy prevention till 2 months post last dose.

Exclusion Criteria:

• Active treatment with corticosteroids or other immunosuppressive agents for acute or chronic rejection.
• More than 2 courses of treatment for acute rejection within last 2 years prior to study enrollment
• History of anaphylaxis or other allergic reaction after receiving prior vaccinations or vaccine components
• Receipt of any inactivated vaccine 8 days before/after dose #1, subunit vaccine 14 days before/after dose #1 and live, attenuated or mRNA vaccine 30 days before/after dose #1
• History of herpes zoster, primary varicella or VZV vaccination within past 1 year prior to study entry
• Active pregnancy as defined by positive pregnancy test at the time of screening and prior to each dose of vaccine
• Febrile illness with Temp ≥39°C and/or infection that require hospitalization or oral antibiotics/antivirals/antifungal/anti-parasite medication within 14 days prior to day 1.
• Any condition that, in the opinion of the investigator, may interfere with optimal participation in the study