#Participants trial#

In the intervention group, geometric mean titres of RBD antibodies increased from 71♴6 BAU/mL (95% CI 59♸4–85♳3) at baseline to 7756♶8 BAU/mL (7371♵3–8161♹6) at day 14 (p<0♰001). 663 (98%) participants (n=441 intervention, n=222 control) completed the study up to day 14. Findingsīetween April 24 and 30, 2021, 676 individuals were enrolled and randomly assigned to either the intervention group (n=450) or control group (n=226) at five university hospitals in Spain (mean age 44 years 382 women and 294 men).

This study is registered with EudraCT (2021-001978-37) and ( NCT04860739), and is ongoing. The safety analysis included all participants who received BNT162b2. The primary analysis included all participants who received at least one dose of BNT162b2 and who had at least one efficacy evaluation after baseline. The safety outcome was 7-day reactogenicity, measured as solicited local and systemic adverse events. Antibody functionality was assessed using a pseudovirus neutralisation assay, and cellular immune response using an interferon-γ immunoassay. The primary outcome was 14-day immunogenicity, measured by immunoassays for SARS-CoV-2 trimeric spike protein and receptor binding domain (RBD). Participants were randomly assigned (2:1) to receive either BNT162b2 (0♳ mL) via a single intramuscular injection (intervention group) or continue observation (control group).

#Participants trial#

We did a phase 2, open-label, randomised, controlled trial on adults aged 18–60 years, vaccinated with a single dose of ChAdOx1-S 8–12 weeks before screening, and no history of SARS-CoV-2 infection. The Lancet Regional Health – Western Pacific.

The Lancet Regional Health – Southeast Asia.The Lancet Gastroenterology & Hepatology.