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NCT06148025
The goal of this clinical trial is to examine immune responses to the BCG vaccine in healthy adults who have, or who have not, taken antibiotics to deplete their gut bacteria prior to vaccination. The main question it aims to answer is: does depletion of the gut microbiota lead to impaired BCG-induced protection against specific and non-specific to challenges to the immune system?
NCT05060991
Immunocompromised individuals, such as solid organ transplant (SOT) recipients are at high risk of COVID-19 associated complications and mortality. Retrospective studies so far have shown that a majority of SOT recipients did not develop appreciable anti-spike antibody response after a first, second, or even third dose of mRNA vaccine. Treatment with antimetabolites was associated with poor vaccine response. The goal of this study is 1) examine whether transient immunosuppression reduction improves the immune response to a third dose of SARS-CoV-2 mRNA vaccine in kidney transplant recipients and 2) to assess the safety of immunosuppression reduction before and after third dose SARS-CoV-2 mRNA vaccination.
NCT05116748
Background: ISHLT and AASLD guidelines recommend SARS-CoV2 vaccination in all individuals undergoing lung and liver transplantation, but there are currently scarce data on the safety and efficacy of these vaccines in this population. In Italy, immunocompromised patients have received the indication to be administered mRNA vaccines only. Primary outcome: safety and reactogenicity Secondary outcomes: immunogenicity and prevention of COVID19 Visits and timepoints: * T0: before first dose administration: visit and venous sampling to assess baseline COVID19 serum status * Telephone calls to assess safety and reactogenicity 1 and 2 days after each dose of vaccination * T21 or 28 (based on vaccine; mRNA BNT162b2 and mRNA-1273, respectively): visit, venous sampling to assess immunogenicity * Follow up visits after 60, 120, 180 and 365 from T0: visit and venous sampling to assess immunogenicity
NCT05791851
The goal of this natural history study is to examine the immune responses to the Heplisav-B vaccine in Veterans living with HIV who were non-responders to prior HBV vaccination. A comparison group of HBV vaccine nonresponders without HIV infection will be enrolled to characterize the HIV-associated immune alterations that affect vaccine response. The investigators hypothesize that TLR9-mediated innate immune stimulation with Heplisav will elicit HBV seroprotection despite prior vaccination failures in persons living with HIV, compared to HIV uninfected individuals. Participants eligible for Heplisav-B vaccination will be asked to provide blood samples at multiple timepoints before and after their vaccination.
NCT03855176
Though HAV is mainly transmitted through the fecal-oral route, infection by sexual intercourse and blood transfusion is also possible. Injection drug users (IDUs) and men who have sex with men (MSM) have a higher risk of acquiring HAV due to their behaviors. Reemerging threat of hepatitis A among MSM in Taiwan has been reported recently. Based on the guidelines for the diagnosis and treatment of HIV/AIDS and the Advisory Committee on Immunization Practices (ACIP), Taiwan, vaccination of individuals against HAV with any of the following indications is recommended: HIV patients, adults with chronic hepatic disease, hemophilia, liver transplantation, occupational exposure, MSM, persons who use injection or noninjection illicit drugs, or persons traveling to or working in countries that have endemicity of HAV. In HIV-infected patients, the immunogenicity to HAV vaccination is sub-optimal in HIV-infected patients and the seroconversion rate is estimated 68-90% after administration of 2 or 3 doses of HAV vaccine. Furthermore, the antibody titers of HIV-infected patients following HAV vaccination are significantly lower compared to those of HIV-uninfected persons. The sub-optimal response among HIV-infected subjects remains an unresolved problem. In this study, the investigators aim to determine the to conduct a randomized clinical trial to compare the immunogenicity of 2 different doses of HAV vaccination (1 dose versus 2 doses) in HIV-infected patients who failed to achieve serologic response in the primary vaccination. This proposal will provide the solid evidence to elucidate the role of booster HAV vaccination in HIV-infected patients without response to primary HAV vaccination.
NCT04743947
This is a prospective, multi-center, observational study that will enroll patients receiving dialysis (hemodialysis or peritoneal dialysis) or patients with kidney transplantation who will be vaccinated against COVID-19.
NCT04059991
Viruses with high mutation rates, such influenza or HIV, pose a major challenge for vaccine design. The current influenza vaccination strategy of yearly vaccination with adapted strains aims to maximally diversify the antibody immune response to prevent viral escape. There is, however, growing evidence, that repeated vaccination with very similar viral proteins might limit, instead of broaden, diversification and thereby reduce vaccine efficacy. The ARIVA Study prospectively studies the immunological impact of repeated influenza vaccination on viral variant recognition and antibody responses in healthy subjects cross-sectionally and over three consecutive vaccination seasons.
NCT05019248
The primary objective of this study is to characterize the antibody response to seasonal influenza vaccine, in patients with active RRMS, treated with cladribine, compared to control individuals with basic immunomodulatory treatment. Serum antibody titers against the respective pathogen will be assessed prior to and 6 to 8 months following vaccination.