Long-term safety and immunogenicity of an MF59-adjuvanted spike glycoprotein-clamp vaccine for SARS-CoV-2 in adults aged 18-55 years or ≥56 years: 12-month results from a randomised, double-blind, placebo-controlled, phase 1 trial.

Background: We previously demonstrated the safety and immunogenicity of an MF59-adjuvanted COVID-19 vaccine based on the SARS-CoV-2 spike glycoprotein stabilised in a pre-fusion conformation by a molecular clamp using HIV-1 glycoprotein 41 sequences. Here, we describe 12-month results in adults aged 18-55 years and ≥56 years.

Methods: Phase 1, double-blind, placebo-controlled trial conducted in Australia (July 2020-December 2021; ClinicalTrials.