View clinical trials related to Vaccination Failure.
Filter by:The current recommendation for a full course of measles-mumps-rubella-(varicella) vaccine (MMR(V)) is two doses. The problem is, many individuals within the vaccinated cohort show antibody levels that are below the level considered to be protective, even after two doses of vaccine. Because of these waning antibody levels, it is currently unknown whether highly vaccinated populations are protected from infection against measles, mumps, rubella, or varicella should they be exposed to any of these viruses. The uncertainty of a woman's immune status is partly due to the type of testing that is used to indicate protection. While immunity to viral infection requires both a humoral and a cell mediated immune (CMI) response, only humoral (antibody) responses are measured routinely in the laboratory. This study will examine CMI responses and the role of a third dose of vaccine for previously vaccinated women whose antibody levels are below the cut off. This study will not administer vaccine, but rather will include women who have received a third dose of vaccination through routine health care follow up in the study cohort.
The specific immune response to SARS-CoV-2 includes a humoral response - specific IgM appearing 5 days after the onset of symptoms while IgG appears after 14 days - and a T lymphocyte component, with specific activated CD8 and CD4 T lymphocytes (Dan JM et al., Science 2021). Mortality from infection varies greatly depending on the age of the affected subjects and their comorbidities including a history of cancer (Liang W et al, 2020). Among these cancers, a history of malignant hemopathy in the 5 years preceding the onset of Covid-19 increases the risk of death by a factor of 3 (OpenSAFELY collaborative 2020). Among them, lymphoid hemopathies induce hypogammaglobulinemia and / or lymphopenia. These factors combined with chemotherapy and immunotherapy treatments promote the development of infections in affected individuals. Among these, are the anti-CD20 monoclonal antibodies, widely prescribed for treating B-cell non-Hodgkin lymphomas (B-NHL). They induce a deep and lasting B-cell lymphopenia, which can promote infections (Maschmeyer G et al, 2019). They reduce the production of antibodies and the constitution of memory responses to a new pathogen or to a vaccination. In addition, B lymphocytes likely have a key immunomodulatory role in the control of viral infections. We conducted a retrospective study in 89 patients with lymphoma and Covid-19 after the first phase of the epidemic in different centers in the Île-de-France and eastern France regions (Lamure S et al. , 2020). With a 6-month follow-up, we showed a pejorative prognostic impact of anti-CD20 monoclonal antibody treatment on Covid-19-related mortality (Duléry et al, 2021). Vaccination of these at-risk patients is therefore essential. A growing concern is how patients with B-NHL who have been vaccinated with a SARS-CoV-2 mRNA vaccine are protected against infection, depending on whether or not they have received anti-CD20 monoclonal drugs and / or chemotherapy. Knowing the medium-term immunological evolution after vaccination against SARS-CoV-2 in patients with B-cell NHL is necessary in order to be able to adapt the therapeutic and vaccine recommendations. The main objective of this study is to determine how recent treatment (in the year before vaccination) with anti-CD20 monoclonal antibody modifies the immune response after vaccination against SARS-CoV-2 in adults with B-NHL compared to patients who have not recently been exposed to this immunotherapy.
In a population of cirrhotics patients who did not responde to an anti-HBV vaccination according to the recommended vaccination, the goal is to : Describe the proportion of patients with HBs antibody levels greater than 10mUI/mL at 1 month of the last injection of vaccine ; with a M0-M1-M6 vaccine regimen using 3 vaccines strategies : - After simple intramuscular vaccine (IM) ( Control group ) - After simple intradermal vaccine - after IMIQUIMOD's application followed by intradermal vaccine administration The main hypothesis of this study is : IMIQUIMOD acts as an immunity booster, so the combination of IMIQUIMOD with an intra-dermal injection of the anti-HBV vaccine allows better acquisition of post-vaccination immunization.
The timeliness of routine childhood immunization should be an important component in measuring vaccination coverage rates especially in LMIC countries like Nigeria, yet this is overlooked. This study will determine the age- specific immunization timely uptake rates for the various vaccines covered in the routine childhood immunization and seek out factors that affect timely vaccine uptake among Nigerian children.