Data from the trial of the Russian COVID-19 vaccine, Sputnik V, have been published in the Lancet.
The paper reports the findings of two open non-randomised phase 1/2 trials of a heterologous COVID-19 vaccine consisting of recombinant adenovirus type 26 (rAd26) vector and recombinant adenovirus type 5 (rAd5) vector, carrying the gene for SARS-CoV-2 spike glycoprotein (rAd26-S and rAd5-S).
The trials enrolled 76 healthy adult volunteers. In phase 1 of each study, participants received one dose of rAd26-S or rAd5-S on day 0. Safety was assessed at 28 days. In phase 2, participants received a prime-boost vaccination.
The most common adverse events were injection site pain (58%), hyperthermia (50%), headache (42%), asthenia (28%), and muscle and joint pain (24%). No serious adverse events were detected, the authors report.
All participants produced antibodies to SARS-CoV-2 glycoprotein. At day 42, receptor binding domain-specific IgG titres were 14,703 with the frozen formulation and 11,143 with the lyophilised formulation. Neutralising antibodies were 49.25 and 45.95, respectively. Seroconversion rate was 100 per cent.
Cell-mediated responses were detected in all participants at day 28. Median cell proliferation was 2.5 per cent CD4+ and 1.3 per cent CD8+ with the frozen formulation, and 1.3 and 1.1 per cent with the lyophilised formulation.