Evaluating a full or fractional third dose Covid-19 vaccines in previously vaccinated adults
- Conditions
- Covid-19C01.748
- Registration Number
- RBR-4vmh6xg
- Lead Sponsor
- Centro de Estudos e Pesquisas em Moléstias Infecciosas LTDA - CePCLI
- Brief Summary
Not available
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Recruiting
- Sex
- Not specified
- Target Recruitment
- Not specified
Males or females aged 18 years old or above; participants willing and able to comply with the study procedure; participants willing and able to provide informed consent prior to screening; participants who received two SinovacButantan vaccine doses at least 4 months, 120 days, prior to enrolment in this study, with a dose interval between each SinovacButantan dose of 14 to 35 days; for females of childbearing potential, willingness to practice continuous effective contraception during the study and a negative pregnancy test on the day) of screening and vaccination
Participants with fever more than 37.5 oC (axillary) or any acute disease at baseline (Day 1) or within the 3 days prior to randomization, febrile participants with mild diseases may be enrolled at the investigator’s discretion; participants with a recent history of COVID-19 (less or equal to 4 weeks prior to visit 1), laboratory confirmed; participants with a history of serious vaccine-related adverse reaction or serious allergic reaction (e.g., anaphylaxis) to any study vaccine component, as described in the last summary of product characteristics for Sinovac/Butantan, AstraZeneca/Fiocruz or Pfizer/Wyeth; participants with a known bleeding disorder that, in the investigator’s opinion, would contraindicate intramuscular injection; participants with any progressive or serious neurological disorder, seizure disorder or history of Guillian-Barré syndrome; participants given treatment with immunosuppressant therapy within the last 90 days, including cytotoxic agents or systemic corticosteroids or planned receipt during the study period, if a short-term cycle of immunosuppressant systemic corticosteroid dose has been used to treat acute disease, the participant should not be enrolled in the study until corticosteroid therapy has been discontinued for at least 15 days prior to the first study vaccination, in case the participant has been on an immunosuppressant dose of a depot, intramuscular or intra-articular corticosteroid, 60 days should be waited for their enrolment in the study. Inhaled/nebulized, intra-articular, intrabursal or topical (skin or eyes) corticosteroids are allowed; participants with autoimmune diseases, other than: Hashimoto thyroiditis, vitiligo, psoriasis, discoid lupus and the like; HIV-positive participants and/or in treatment for HIV; participants given any other investigational product within the 30 days prior to Day 1 or who intend to take part in another clinical trial at any time during this study conduction; participants given any other licensed vaccine within 14 days prior to enrolment in this study or who plan to receive any vaccine up to 28 days after vaccination; participants given treatment with Rituximab or any other anti-CD20 monoclonal antibody within 9 months prior to Day 1 or planned during the study period; administration of intravenous immunoglobulins and/or any blood products within 3 months prior to enrolment or planned dosing during the study period; participants with any condition that, in the investigator’s opinion, could interfere with the status primary objectives or represent an additional risk for the participant; participants who have received any other vaccine for Covid-19 other than two Sinovac/Butantan doses
Study & Design
- Study Type
- Intervention
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method To assess the immune response measured as binding antibodies (IgG ELISA) following vaccination with a fractional dose of AstraZeneca/Fiocruz or a fractional dose of Pfizer/Wyeth vaccine or a full dose of AstraZeneca/Fiocruz vaccine given as single additional dose in Adults (= 18 years) previously vaccinated with Sinovac/Butantan doses.;To describe the safety and reactogenicity profile of a fractional doses of AstraZeneca/Fiocruz or a fractional dose of Pfizer/Wyeth vaccines or a full dose of AstraZeneca/Fiocruz vaccine given as single additional dose in participants previously vaccinated with two Sinovac/Butantan doses.
- Secondary Outcome Measures
Name Time Method To determine seroresponse rate at 28 days post study vaccine in participants seronegative prior to study vaccination.;To assess the humoral immune response based on additional assays / readouts from fractional and full dose of study vaccine given as an additional dose.;To describe CMI following fractional and full dose of study vaccines given as an additional dose in a subset of participants.