Safety and immunogenicity of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine in two formulations: two open, non-randomised phase 1/2 studies from Russia

In two Phase 1/2 open-label studies (n=76), frozen and lyophilised formulations of a heterologous, recombinant adenovirus vector-based Covid-19 vaccine were immunogenic in all participants, inducing humoral and cell-mediated responses, with a good safety profile.

SPS commentary:

A related comment notes this vaccine candidate joins two other adenovirus-vectored Covid-19 vaccine candidates, that have been reported in randomised trials and an mRNA candidate reported in a non-randomised trial. Similar to these, this study is promising but small. Although the demonstrated immunogenicity ‘bodes well’, clinical efficacy for any Covid-19 vaccine has not yet been shown.


The Lancet

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