Russia has announced its Sputnik V COVID-19 vaccine is effective in 92% of cases.

The news comes two days after Pfizer Inc. (NYSE:PFE) and BioNTech (NASDAQ:BNTX) said their candidate works over 90% of the times.

READ: Which Covid vaccine candidates are competing against Pfizer?

President Vladimir Putin boasted the world’s first coronavirus vaccine to be registered on August 11, but its speed was met with scepticism.

Experts warned the Russian data, albeit encouraging, was based on a small number of participants compared to other companies’ clinical trials.

For instance, the results for Sputnik V were based on 20 volunteers contracting the virus, against 94 participants in Pfizer’s studies, Reuters reported.

Although Pfizer and BioNTech are submitting the candidate for emergency authorisation in the US next week, they are waiting for 164 COVID-19 cases to end the analysis.

The Russian Direct Investment Fund, which supports the development of Sputnik V, said the 40,000-people trial is continuing for another six months.

There were no unexpected adverse events recorded aside from short-term minor effects such as pain at the injection site, flu-like syndrome including fever, weakness, fatigue, and headache.

“The publication of the interim results of the post-registration clinical trials that convincingly demonstrate Sputnik V vaccine’s efficacy gives way to mass vaccination in Russia against COVID-19 in the coming weeks,” said Alexander Gintsburg, director of the Gamaleya Institute which developed the vaccine.

“Thanks to the production scale up at new manufacturing sites, Sputnik V vaccine will soon be available for a wider population. This will break the current trend and lead to an eventual decrease in COVID-19 infection rates, first in Russia, then globally”