Trial NCT05087368
Publication Costa Clemens, Open Forum Infect. Dis., 2022
Dates: 2021-11-26 to 2022-03-07
Funding: Mixed (The study was sponsored by Clover Biopharmaceuticals Inc. and was supported by grant from the Bill & Melinda Gates Foundation. The ChAdOx1-S vaccine used in the study was generously provided by the Ministry of Health (Brasília, Brazil).)
Conflict of interest: Yes

Methods
RCT
Location : Multicenter / Brazil
Follow-up duration (months): 2.53
boosters after ChAdOx1: 9 mcg SCB-2019 + alum (n = 30)
9 mcg SCB-2019 + CpG + alum (n = 29)
30 mcg SCB-2019 + CpG + alum (n = 32)
ChAdOx1 (n = 29)
Inclusion criteria
  • Male or female
  • adults ≥18 years of age
  • who had previously received 2 doses of ChAdOx1-S1-S vaccine 6 months (±4 weeks) before enrollment
  • were willing and able to comply with the study requirements, including all scheduled visits, vaccinations, laboratory tests, and other study procedures
  • being healthy or having a preexisting but stable medical condition at the screening examination
  • a stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 3 months before enrollment
  • Female participants are eligible to participate in the study if not pregnant, not breastfeeding, and at least 1 of the following criteria apply: Women of non-childbearing potential, or Women of childbearing potential must have a negative urine pregnancy test prior to study vaccination. A confirmatory serum pregnancy test may be conducted at the investigator's discretion. They must be using a highly effective licensed method of birth control for 30 days prior to the first vaccination and must agree to continue such precautions during the study until 90 days after the last study vaccination
  • Male participants must agree to employ acceptable contraception from the day of first dose of the study vaccine/comparator until 6 months after the last dose of the study vaccine/comparator and also refrain from donating sperm during this period.
Exclusion criteria
  • Any previous laboratory-confirmed SARS-CoV-2 infection.
Interventions
Intervention
1 IM dose 9 mcg SCB-2019 + alum, >6 months after 2-dose ChAdOx1 primary schedule
1 IM dose 9 mcg SCB-2019 + alum + CpG-1018, >6 months after 2-dose ChAdOx1 primary schedule
1 IM dose 30 mcg SCB-2019 + alum + CpG-1018, >6 months after 2-dose ChAdOx1 primary schedule
Control
1 IM dose ChAdOx1, >6 months after 2-dose ChAdOx1 primary schedule
Participants
Randomized
120 participants
Characteristics of participants
Type of participants: Adults
N=120
52 males
Children: 0
Pregnant women: 0
Mean age:
Age range: 20-66
Description of participants
Adults including healthy or stable co-morbidities with no history of SARS-CoV-2 infection who had previously received 2 doses of ChAdOx1-S1-S vaccine 6 months (±4 weeks) before enrollment in 3 centers in Brazil
Primary outcome
In the register
Immunogenicity : Immunogenicity is defined as the ability of cells/tissues to provoke an immune response and is generally considered to be an undesirable physiological response, as measured by ELISA (homologous strain) and virus neutralization assay (homologous and heterologous strains). (Days 1, 15, 29)
In the report
Immune response assessed by enzyme-linked immunosorbent assay (ELISA) as immunoglobulin G antibodies against SCB-2019 S-protein on day 15... ELISA antibody titers against SCB-2019 S-protein expressed as geometric mean titers (GMTs), geometric mean-fold rise in titers over baseline (GMFR), and seroconversion rates (SCRs) on days 15 and 29. Seroconversion was defined as a≥4-fold increase in post-vaccination titer in those with a baseline titer above the lower limit of quantitation (LLOQ) or a postvaccination titer ≥4-fold the LLOQ in those with no detectable activity at baseline.
Documents
available

Protocol

NR

Statistical plan

*

Data-sharing stated: Yes, After publication in a peer-reviewed journal
Data accessibility: All data produced in the present study are available upon reasonable request to the authors subject to prior publication of the manuscript in a peer-reviewed journal. R. Clemens, MD, PhD - clemens.ralf@outlook.com.

Risk of bias
Overall
The overall risk of bias reported in the table corresponds to the highest risk of bias for the outcomes assessed for the systematic review
Some concerns
General comment In addition to the published article, the trial registry was used in data extraction and assessment of risk of bias. Neither protocol, statistical analysis plan was available. There were no important differences between registry and published report in population, procedures, interventions or outcomes. The trial had no formal target sample size, with the sample recruited being judged sufficient for dosage selection.