Gam-COVID-Vac (Sputnik V): a heterologous adenoviral vector-based COVID-19 vaccine

Abstract

The Sputnik V COVID-19 vaccine (Gam-COVID-Vac) is an adenoviral vector-based vaccine against the SARS-CoV-2 virus developed by Gamaleya National Research Centre for Epidemiology and Microbiology in Moscow, Russia. It consists of two recombinant adenovirus vectors; type 26 (rAd26) and type 5 (rAd5), with a heterologous approach used to reduce the risk of immune responses against the vector component. Findings from published studies showed that Gam-COVID-Vac was relatively safe, with mostly mild local and systemic reactions reported. Both rAd26-S and rAd5-S had to be administered to develop effective neutralising antibodies. No cross-reactive neutralising antibodies against the viral vector component was identified. The phase 3 trial performed in Russia only demonstrated an efficacy of 91.6% in preventing COVID-19 disease. Common adverse events were flu-like symptoms, injection site reactions, headaches and asthenia, of which the majority were mild. Results from ongoing studies using Gam-COVID-Vac in Belarus, United Arab Emirates and India would be useful to demonstrate generalisability to other population groups. Details of adverse events and ongoing safety surveillance data are awaited before submission for regulatory approval.

Keywords: Adenovirus Vaccines, COVID-19, Russia, vaccines