A small-scale clinical study of the combined use of the AstraZeneca and Sputnik Light vaccines against Covid-19 has shown strong antibody growth in a majority of the study's participants, the Russian Direct Investment Fund has said, according to Reuters.

The data was collected from 20 people who took part in a 100-person study in Azerbaijan that began in February. They first received the AstraZeneca shot followed by the one-dose Russian-made Sputnik Light shot 29 days later, the RDIF said.

"According to the results of the interim analysis, a fourfold or higher increase in neutralising antibodies to the spike protein (S-protein) of the SARS-CoV-2 was found in 85 per cent of the volunteers on the 57th day of the study," RDIF said.