| Recruiting | Is a Third Dose of MMRV Vaccine Beneficial for the Adult Population in Alberta? NCT05923970 | University of Alberta | — |
| Recruiting | RSV Vaccine in Transplant Recipients NCT06593210 | University Health Network, Toronto | Phase 3 |
| Recruiting | Safety and Immunogenicity of Recombinant Zoster Vaccine for Transplant Recipients NCT06262776 | Central Adelaide Local Health Network Incorporated | N/A |
| Recruiting | Antibiotics and Vaccine Immune Responses Study NCT06148025 | South Australian Health and Medical Research Institute | Phase 4 |
| Completed | Immune Response to SARS-CoV-2/COVID-19 Vaccination in Sarcoidosis NCT05089565 | Northwestern University | — |
| Completed | RECOVAC Repeated Vaccination Study NCT05030974 | University Medical Center Groningen | Phase 4 |
| Completed | Immune Response to Third Dose of COVID-19 Vaccine in Solid Organ Transplant NCT05124509 | Pontificia Universidad Catolica de Chile | — |
| Completed | COVID19 Vaccine in SOT Adult Recipients NCT05116748 | Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico | — |
| Active Not Recruiting | Impact of Immunosuppression Adjustment on COVID-19 Vaccination Response in Kidney Transplant Recipients NCT05060991 | University of California, Davis | Phase 4 |
| Completed | Immune Response to the COVID-19 Vaccine NCT04936997 | University of Arizona | EARLY_Phase 1 |
| Completed | Iron and COVID-19 Vaccine Response NCT04915820 | Jomo Kenyatta University of Agriculture and Technology | N/A |
| Completed | Iron and Vaccine Response NCT04912661 | Swiss Federal Institute of Technology | N/A |
| Completed | Third Dose of Moderna COVID-19 Vaccine in Transplant Recipients NCT04885907 | University Health Network, Toronto | Phase 4 |
| Unknown | Immunogenicity of Covid-19 Vaccination for Patients With Hematological Malignancies NCT04878822 | Ospedale di Circolo - Fondazione Macchi | — |
| Completed | Efficacy and Safety of the Anti- COVID-19 Vaccin in Clinical Hematology Patients NCT04852796 | Centre Hospitalier de Cornouaille | — |
| Terminated | Vaccine Observation to Include All Communities for Equitable Science NCT04770649 | Persephone Biosciences | — |
| Unknown | COVID-19 Vaccine Efficacy in Patients With Malignant Pathologies NCT04776005 | Assistance Publique - Hôpitaux de Paris | — |
| Unknown | Vaccination Against COVID-19 in Chronic Kidney Disease NCT04743947 | Heinrich-Heine University, Duesseldorf | — |
| Unknown | Immune Response to Seasonal Influenza Vaccination in Multiple Sclerosis Patients Receiving Cladribine NCT05019248 | Heinrich-Heine University, Duesseldorf | — |
| Completed | Heplisav-B Revaccination for Hepatitis B Vaccine Nonresponders NCT05791851 | University of Maryland, Baltimore | — |
| Completed | Vaccination Efficacy With Metformin in Older Adults NCT03996538 | UConn Health | Phase 1 |
| Completed | Impact of Metformin on Immunity NCT03713801 | The University of Texas Health Science Center at San Antonio | Phase 1 |
| Completed | Pregnancy, Arsenic and Immune Response NCT03930017 | Johns Hopkins Bloomberg School of Public Health | — |
| Completed | Antibodies in Repeated Influenza Vaccination (ARIVA) Study NCT04059991 | University Hospital, Basel, Switzerland | — |
| Completed | Effectiveness of Booster With 1 or 2 Doses of HAV Vaccine Among HIV-infected Patients NCT03855176 | National Taiwan University Hospital | Phase 4 |
| Unknown | Immunogenicity of the Hepatitis B Vaccine NCT04540653 | Universidade Federal de Goias | Phase 4 |
| Completed | The Effects of Increased Inoculum on Oral Rotavirus Vaccine Take and Immunogenicity NCT02992197 | University of Vermont | Phase 4 |
| Completed | Study of Environmental Enteropathy and Malnutrition in Pakistan NCT03588013 | Aga Khan University | N/A |
| Completed | Immunogenicity of Co-administered Yellow Fever and Measles, Mumps, and Rubella (MMR) Vaccines NCT03368495 | Alba Maria Ropero | Phase 4 |
| Completed | Immune-Related Trafficking and Signaling in Human Skin Associated With Low-Power, Infrared Laser Treatment NCT02453113 | University of California, Irvine | N/A |
| Completed | Role of Interferon-λ and Vaccine Response NCT03467074 | University Hospital, Basel, Switzerland | — |
| Unknown | Three Doses of Hepatitis A Vaccine in Patients With Immunomodulating Drugs NCT01446978 | Sormland County Council, Sweden | Phase 2 |
| Completed | Vaccine Hyporesponse in Healthy Elderly Participants (MK-0000-131 AM2) NCT01119703 | Merck Sharp & Dohme LLC | — |