Russia's Sputnik V vaccine provides a strong defence against serious symptoms and hospitalisations caused by the Omicron coronavirus variant, the RDIF sovereign wealth fund has said, citing a preliminary study by the vaccine developer.

When used as a booster shot, Russia's single-dose Sputnik Light helps develop a stronger antibody response against the Omicron variant, the study by the Gamaleya Institute developer was cited by Reuters as saying.

The preliminary data from Gamaleya showed that the efficacy of Sputnik V with the Sputnik Light booster against Omicron could be more than 80 per cent.

RDIF said the preliminary lab study by Gamaleya demonstrated that Sputnik V demonstrates “high virus neutralising activity” (VNA) against Omicron.