View clinical trials related to Vaccine Response Impaired.
Filter by: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.
The Coronavirus Disease 2019 (COVID-19) pandemic has claimed over 5 million lives globally. Fortunately, a substantial and growing number of SARS-CoV-2 vaccines with very high efficacy have been developed, manufactured, and rapidly approved. Novel mRNA vaccines such as the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) have reported a stunning >94% efficacy against COVID-19. However, global access has not been equitable, with many low- and middle-income countries having no vaccine access or access under emergency use mainly to traditional inactivated SARS-CoV2-2 vaccines such as BBIBP-CorV (Sinopharm Beijing), CoronaVac (Sinovac) and BBV152 (Bharat Biotech). Emerging studies have shown that lower concentrations of neutralizing antibodies (Nab) are attained after CoronaVac than after an mRNA-based vaccine in healthy individuals. This difference seems to be more pronounced in immunocompromised patients who are at higher risk of severe COVID-19 and death from COVID-19. As such, several countries including the United States, Israel and Chile have recommended a third vaccine dose for high-risk populations. However, it is not currently known which is the best vaccine combination regarding immunogenicity, particularly in these vulnerable patients. This observational study will explore the humoral and cellular response to a SARS-CoV-2 BNT162b2 vaccine booster in solid organ transplant patients who received two previous doses of the inactivated Coronavac or two doses of BNT162b2 vaccines.
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
People with sarcoidosis, particularly those with significant lung and/or cardiac involvement, who become infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) are likely at increased risk of complications or death from COVID-19. While SARS-CoV-2 vaccines are highly efficacious in preventing COVID-19 in the general population, whether vaccination provides similar protection in people with sarcoidosis is unknown. The investigators hypothesize that people with sarcoidosis develop less robust antibody and cell-mediated immune responses to SARS-CoV-2 vaccination than healthy individuals, both as a consequence of the disease itself and due to treatment with immunosuppressive medications. This hypothesis will be examined by determining levels of anti-SARS-CoV-2 spike protein immunoglobulin G (IgG) antibody (Specific Aim 1) and measuring SARS-CoV-2-specific activation of peripheral blood T cells (Specific Aim 2) following SARS-CoV-2 vaccination in individuals with sarcoidosis treated and not treated with immunosuppressive medications, in comparison to age- and sex-matched healthy controls. For Specific Aim 1, a second-generation anti-SARS-CoV-2 spike IgG assay calibrated against an independent virus neutralization assay will be utilized. The results of this investigation will address a critical gap in the understanding of vaccine responses in people with sarcoidosis. In addition, the study will contribute knowledge needed to inform clinicians' recommendations to sarcoidosis patients regarding risk of infection after SARS-CoV-2 vaccination, and will help lay the basis for future trials to evaluate the possible benefit of vaccine boosters in individuals with poor immune responses to initial vaccination.
Rationale: The humoral and cellular immune response after two mRNA vaccinations is severely attenuated in kidney transplant patients compared to controls, especially when their immunosuppressive regimen contains mycophenolate mofetil (MMF) / mycophenolic acid (MPA). A repeated dose strategy is therefore required to improve the efficacy of vaccination. Objective: To investigate the immunogenicity of third or fourth dose SARS-CoV-2 vaccination strategies in kidney transplant patients. Study design: Prospective, multicentre, open-label randomized clinical trial Study population: Patients with a functioning kidney transplant who did not seroconvert after two or three doses of a mRNA vaccine (either mRNA-1273 (Moderna) or BNT162b2 (Pfizer) or any combination of both) Procedures: Based on their immunosuppressive treatment, patients can participate in one of the following strata: - stratum A: patients receiving triple immunosuppressive therapy, consisting of a calcineurin inhibitor, MMF/MPA, and steroids In stratum A, patients will be randomized to one of two equally sized groups. Patients will receive a third or fourth vaccination of the mRNA-1273 vaccine (100 μg, i.m), with either continuation of MMF/MPA (A1) or discontinuation of MMF/MPA during one week before and one week after the third or fourth dose, respectively (A2). - stratum B: patients receiving any combination of immunosuppressive drugs. In stratum B, patients will be randomized to one of three equally sized groups. Patients will receive another dose (100 μg, i.m) of the mRNA-1273 vaccine (B1), or two single doses of mRNA-1273 into the left and the right upper arm (2 x 100 μg, i.m; B2), or the Ad26.COV2.S vaccine (Janssen, 5x1010 viral particles, i.m; B3). Main study parameters/endpoints: The primary endpoint is the proportion of patients with an anti-S1 antibody concentration higher than 10 BAU/mL established at 28 days after the third or fourth vaccine administration. Within each stratum different vaccination strategies will be compared. Secondary endpoints include: - concentration of anti-S1 antibodies in serum at 28 days after the 3rd or 4th vaccine administration - concentration of virus-neutralizing antibodies in serum - SARS-CoV-2 specific T cell responses - safety in terms of incidence of acute rejection and solicited local and systemic adverse events (AEs) after vaccination. - antibody (IgG and IgA) responses in nasal mucosal fluid
Explore the effects on immune response to include a potential third vaccine for the cancer cohort.
Vaccines often underperform in Africa compared to high-income countries. Why vaccines do not work as well in Africa remains uncertain. Malnutrition likely plays a role. Our study objective is to assess whether iron deficiency anaemia in young women impairs their immune response to the COVID-19 vaccine, and whether iron treatment improves their response.
Vaccines often underperform in Africa compared to high-income countries. Why vaccines do not work as well in Africa remains uncertain. Malnutrition likely plays a role. Our study objective is to assess whether iron deficiency anaemia in young women impairs their immune response to viral vaccines, and whether iron treatment improves their response.
This study will be a randomized, double-blind, placebo-controlled trial of a third dose of Moderna vaccine versus placebo. Participants will be those that have received two doses of mRNA-1273 COVID vaccine (Moderna) at 0 and 1 months. Participants will be randomized 1:1 to receive either a third dose of the mRNA-1273 vaccine or saline placebo at 3 months post initial vaccination.
Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that was first reported in December 2019 in Wuhan, China. Infection with this new coronavirus called SARS-CoV-2 can lead to fatal pneumonia associated with high rates of hospitalization in intensive care units (ICU). Hospitalized patients with hematologic malignancies have a higher mortality rate than patients without hematologic malignancies (62% vs. 8%). The severity of Covid-19 may be related to their treatment, in particular anti-CD20 used in B lymphoid hemopathies. In fact, anti-CD20 antibodies induce rapid and prolonged depletion of B cells, but they are necessary for development. humoral immune responses. But currently, no immunogenicity data are known for patients with hemopathy or in those on anti-lymphocyte immunochemotherapy.